#geometry-and-trigonometry

1 messages · Page 370 of 1

heavy snow
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sure hold on

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area = 15 and perimeter = 16,4

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I think thats how you say it

dark sparrow
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yes

heavy snow
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O = 5 + 4 + 5,38 + 2 = 16,38 A = 5*((2+4)/2) = 15

dark sparrow
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so then why did you say that the book said perimeter = 15

heavy snow
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mixed up the words there, sorry

hearty rain
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@forest drift ...

forest drift
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you want that proof?

dark sparrow
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you've been all promises and no delivery, anish bhat

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you know this makes you look very suspicious at best, right?

earnest basin
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Help

heavy snow
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if the task is to solve what coordinates say B has in the line AB if what is given to you is only A = (5,2) and the midpoint M = (-1, 1) how would you solve it?

dark sparrow
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the midpoint, as in the midpoint of AB?

heavy snow
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I assume the midpoint here is between A and B

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my first thought is to find out the length of A and M and then double it to find B?

dark sparrow
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you will only find the length of AB

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which won't help you much

heavy snow
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B is supposed to be (-5, 4)

dark sparrow
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it's better to remember how you would find the midpoint given A and B

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$M = \paren{\frac{x_A + x_B}{2}, \frac{y_A + y_B}{2}}$

somber coyoteBOT
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Kanga Gang Annihilator Ann

heavy snow
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right and that gives me an equation

dark sparrow
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two equations

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one for x, one for y

heavy snow
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the Y equation is quite difficult to solve

dark sparrow
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is it?

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it should not be any more difficult than the x equation

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they have the exact same structure just with different numbers

heavy snow
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2 * (3 + x) / 2 = -1 * 2
3 - 3 + x = -2 - 3
x = -5

dark sparrow
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and you had difficulty going through the exact same motions with (y+2)/2 = 1?

heavy snow
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actually I was doing something wrong

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got it

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2 * (-2 + y) / 2 = 1 * 2
-2 + y = 2
2 + -2 + y = 2 + 2
y = 4

dark sparrow
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you said A = (5, 2) not A = (5, -2)

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but ok

heavy snow
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sorry I was looking at the wrong task it should be A = (3, -2) B = (?,?) and M = (-1, 1)

dark sparrow
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ah.

heavy snow
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thats why I got Y wrong there

hearty rain
upper karma
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how do we visualize the graph by reflection of a function f(x) at a given line like y=x. Is there any way we could visualize this in a nice easier way rather than plotting all the points?

heavy snow
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is the midpoint normal between a line AB just another name for a midpoint?

upper karma
heavy snow
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visualize as in using your imagination or an actual graph tool?

upper karma
heavy snow
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put in the function here and practice visualization?

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would be my take on it

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if you actually know what it looks like then you can approximate a similar function

upper karma
upper karma
heavy snow
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stuff like this?

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otherwise I don't know because it sounds beyond my knowledge

upper karma
forest drift
heavy snow
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no you didnt

forest drift
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I just proved another case of ramanujan correct

dark sparrow
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......

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okay so you misled us all

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that's not very nice

forest drift
forest drift
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k

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nice

heavy snow
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stop spamming these boards with nonsense

dark sparrow
upper karma
# heavy snow no you didnt

suppose u're given a function and how do u know it's graph after reflection along y=x will be like you've drawn in the ss u've sent.. plz tell me. that's the thing i'm havin' dilemma over

heavy snow
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well put in the function you have into that graph there and it'll draw it for you

upper karma
heavy snow
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what does the function you are trying to solve look like?

forest drift
dark sparrow
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you hope that we hate you?

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weird but ok

forest drift
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you hate me right?

dark sparrow
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no

wise pawn
forest drift
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I'll send my proof

heavy snow
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you can send it down the toilet

forest drift
heavy snow
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how do you find the midpoint normal of a line AB if A = (1,0) and B = (5,4) ?

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erm the task is to write it as a linear equation, y=kx+m

nocturne remnant
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midpointnormal?

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you sure you didn't mean perpendicular bisector?

heavy snow
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yes thats the correct term

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I didn't know what it was called

nocturne remnant
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welp i think i have one way to do it

forest drift
heavy snow
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(1 + 5) / 2, (0 + 4) / 2 = M(3, 2)

forest drift
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mid point is (3,2)

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so use basic graphing to find the equation of line

nocturne remnant
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alternatively, any point T(m,n) lies on the desired line if TA = TB
so you might be able to just plug the distance formula or sth

heavy snow
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y = 3x + 2

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but for some reason the facts wants it to be y = -x + 5

nocturne remnant
heavy snow
nocturne remnant
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...

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the line y = 3x + 2 very clearly does not pass through (3,2)

forest drift
heavy snow
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how do you find it then without using the graph tool?

forest drift
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or maybe

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just find the locus

nocturne remnant
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does the question tell you to use a graph?

heavy snow
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no

nocturne remnant
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well you cant use a graph in the exams

heavy snow
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it gives you the A and B points and then you are supposed to determine the equation to the perpendicular bisector

nocturne remnant
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was there a similar-type problem in the lesson / handouts / textbooks?

heavy snow
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surprisingly nothing

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and I looked it up and other people have being asking the same question when it comes to this problem

dark sparrow
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well i would suggest writing out (x-1)^2 + y^2 = (x-5)^2 + (y-4)^2, expanding it out and letting the algebraic dust settle

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but i'm almost certain that wouldn't go well

nocturne remnant
dark sparrow
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this is just TA^2 = TB^2 in elon mask's notation

nocturne remnant
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so yeah, either plug the distance formula
or find the mid-pt, and then the desired slope in order to construct the eqn

heavy snow
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well I solved the mid-pt (1 + 5) / 2, (0 + 4) / 2 = M(3, 2)

dark sparrow
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sure, that's going to be your midpoint

nocturne remnant
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desired line should be perpendicular to the original line AB

dark sparrow
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if you want to do it that way, the next step would be to find the slope of the line AB and take its negative reciprocal

heavy snow
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so you inverse AB ?

nocturne remnant
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find the slope of AB first

heavy snow
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so rise/run = 4/5 = 0,8

nocturne remnant
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hmm

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the slope should be || 1 ||

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rise and run are both 4

heavy snow
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ah I see you start from where the point is at

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I was counting from 0

nocturne remnant
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so, the slope of AB is 1

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what should the slope of our answer line be?

heavy snow
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not sure maybe (2, 1) ?

nocturne remnant
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slope!

heavy snow
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I don't know how you do that

nocturne remnant
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a slope is a number

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(Any two perpendicular lines have their slopes multiply to -1)

heavy snow
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1 ?

nocturne remnant
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well AB is 1

heavy snow
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1 * -1 = -1

nocturne remnant
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so the required slope is?

heavy snow
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-1 I guess?

nocturne remnant
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Yep!

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So, we already have the slope, and that the line passes through (3,2)

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now, you should be able to find the y=mx+c

heavy snow
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my mind is blank, I have no idea

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slope is the x? so y = -x + something

nocturne remnant
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yes

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just sub x = 3, y = 2 to find the "something"

heavy snow
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you mean add? 3 +2 = 5

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3 -2 = 1

nocturne remnant
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y = mx + c
sub x = 3, y = 2, m = -1

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what is c?

heavy snow
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what do you mean sub x = 3, y = 2, m = -1?. 3 - 2 + -1 ?

nocturne remnant
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substitution

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juse replace the letters in the equation with the corresponding numbers

heavy snow
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2 = -3x + -1 ?

nocturne remnant
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?

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be careful

heavy snow
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2 = 3 - 1 unless you count out the -x slope

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I'm just guessing because I don't know how you'd approach this

nocturne remnant
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???

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this is basic algebra

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substituting

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y = mx+c
2 = (-1)(3) + c

heavy snow
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weeeell that explains it

nocturne remnant
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yeah c is 5

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problem solved.

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bye

heavy snow
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wouldn't have been easier just to show me that to begin with?

nocturne remnant
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well i didnt think you'd get stuck on such a thing

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since you know about midpoints and stuff

heavy snow
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how am I supposed to know you are supposed to solve it this way?

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its the reason I asked for help to begin with

nocturne remnant
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but whatever

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bye

heavy snow
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for you it is, not me, okey, thanks, bye

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its a common pattern I've noticed when you ask for help about a math problem. People just assume you know everything already and they are too lazy to imagine why the person who is asking for help is thinking in a particular way about a problem. If you can imagine what the person who is asking for help is thinking which leads to the wrong answer, you can also guide and show that person the correct way of thinking.

hearty rain
upper karma
molten delta
abstract fog
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In the supplementry formula we use =180

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So we will have
90 + 3x + 2x-20= 180

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70 + 5x = 180 we combine like terms

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5x= 110

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x= 22

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We know x is 22 but we are not done yet

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It wants to know what angle c is

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So we now go (2*22 - 20)

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44-20

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24

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So we get our answer which is m<c is equal to 24

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Hopefully I got it right and you understand

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@hexed tiger

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Did I do the work correctly

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I’m not that good at geometry and idk if I am leading in wrong path

loud vale
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hey guys does anyobdy want to join help 1 with me

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its on solving equations

upper karma
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What does x positive mean over here as highlighted in the blue text? Can x ever be considered negative? How could distance be negative? Plz tell

humble pulsar
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but distance is strictly non-negative, yes

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Because you use right angle trig, you restrict yourself to only considering positive x

upper karma
lunar heart
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excuse me can anyone help me with geometry

humble pulsar
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Then the argument doesn't hold

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Cause you wouldn't have a triangle

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Or.. if you impose it on the unit circle then you'd just get the triangle the other way, so it should actually work in technicality?

earnest basin
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Circle M has a central angel of 100 degrees with radius 12 cm. Find the area of the segment.

54.75 sq. cm
4.56 sq. m
10.47 sq. cm
76.46 sq. cm

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Helppppp

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<@&286206848099549185>

signal swallow
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also multiple choice leads me to believe it's a test/quiz

sacred wyvern
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I really don't understand trigonometry much could anyone help me what exactly it is I tried going through some websites for them but I still didn't understand it?

dark sparrow
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somewhat loosely, trigonometry is the study of the relationship between lengths and angles in triangles (and in other shapes that can be built up from triangles)

fallen sleet
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how to prove that a circle has a finite perimeter?

dark sparrow
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i guess you would need to work with the definition of a rectifiable curve

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ie the definition of what it means for a curve to have a length in the first place

fallen sleet
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does this mean changing the definition of a rectifiable curve [for example making it x2] would not cause any issues? [even if it is not useful]

dark sparrow
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i think you misunderstand

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the definition of a rectifiable curve concerns what curves have a length in the first place, not the assignment of lengths to curves

fallen sleet
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oh my bad

silk jacinth
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I know this solution I saw is wrong, but my sleep- and glucose-deprived brain figure out why:

tan x = sin x
sin x / cos x = sin x
sin x / cos x = sin x / 1
cos x = 1
x = 2πn

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oh wait now I get it, if sin x = 0, then cos x might not be 1

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so yeah nevermind 😄

humble pulsar
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tan(x)-sin(x)=0 then factor

silk jacinth
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yeah that's how I did it

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but someone gave that solution and I couldn't immediately find the error in their reasoning

empty thicket
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Hi anyone know how to do proofs

humble pulsar
twin axle
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Can someone help me with a very easy trig identities q

upper karma
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2SINxCOSx = SIN(2x)

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1 = cos²x+ sin²x

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you know these formulas?

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or not?

opaque mauve
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Hello I need some help with geometry

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My teacher gave me this and idk where to start

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This is a example of what I need to do

tribal tendon
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@nocturne pebble

forest drift
forest drift
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can you come to DMs

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I can help you out

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for the first question

opaque mauve
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It’s ok I finished it already

forest drift
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okk

forest drift
opaque mauve
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@trail tree helped me

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🙏👍

heady adder
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Hello

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@forest drift pranam ramanujan ji

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I was playing with this simulation and i am unable to understand how 230° is found here.

dark sparrow
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@heady adder

heady adder
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Thanks

forest drift
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ramanujan ka pranam

potent orbit
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Anyone know about this?

heavy snow
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direction is the length of p2-p1

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the line started at point p1(2.5) and ended at point p2(11,13)

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you then take the origin or p1 * direction * force which is 2,8

potent orbit
heavy snow
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sure

dense badger
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can somone help me with this

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its like a summative but i am confused on a and c

dense badger
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nvm got c can somone help with a

upper karma
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Sec=1/cos

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And cot=cos/sin

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So 1/cot= sin/cos

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And sinsec= sin/cos

dense badger
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oh

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what about a

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i solved c

upper karma
dense badger
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oh

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yea

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like i was confused when us aid taht was b

upper karma
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Sorry i wrote it wrong

dense badger
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nah all good

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any idea on b

upper karma
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Yes

dense badger
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how

upper karma
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1-cos²x=sin²x

dense badger
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wait how sin 2 x

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how did u get that

upper karma
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That is thé basic formula of goniometri

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Cos²a+sin²a=1

dense badger
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oh wiat

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i see

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yea

upper karma
#

Is your problem solved?

dense badger
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yea

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i got it

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ik what to do

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just needed these hints

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thanks a lot

upper karma
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Ok

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Done with pleasur

upper karma
#

Give every Point a letter first

potent orbit
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I figured it out, sorta, but i do have a more complex one

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Here's the one I'm talking about

upper karma
#

So and than you look first for side AD

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You know the formules?

upper karma
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It doesnt matter if the picture is bad it is vetter than No picture

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Better

potent orbit
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Seriously? You don't know how to help if there isn't a picture involved?

viscid ginkgo
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this is often my problem with my classes where I feel like people don't explain things properly

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I look all over for the answer and spend so much time confused

upper karma
#

You put 2.5π in your function

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And 2.5π-π=1.5π

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And than (1/3)•1.5π=(π/2)

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π/2=90°

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Sin 90°= 1

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So (2•1)+4=6

upper karma
upper blaze
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Guys I have a question

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Does anyone know how much 3D geogebra calculations are precise?

onyx mesa
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im stuck

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i dont know how to prove the last part

viscid ginkgo
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thank you sir

upper blaze
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You have all 3 angles and 1 common side

onyx mesa
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you have to get the shortest proof possible so stating it's right triangles wouldnt count

onyx mesa
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can someone help me

upper blaze
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Hmmm but thats shortest? I dont see what shorter you want xD

forest drift
dark sparrow
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great, who cares

upper blaze
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Anish, I think you should be more respectfull to others and if you cant help them dont comment. If you have something usefull to say please do otherwise dont say anything. You alredy trolled here before now please stop

upper blaze
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About ramanujan proof?

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I have never saw your work

forest drift
forest drift
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I have done it but I am hesitant to show it to others cuz you guys might steal

upper blaze
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yea yea

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dont argue here

forest drift
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then come to DMs

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guys doubt

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pls help

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nvm i got it

dark sparrow
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I have done it but I am hesitant to show it to others cuz you guys might steal
lmfao

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wow

upper blaze
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Fast Geogebra question. If I have a regular triangle in some plane in space how can I make tetraheadron over that triangle so that 4th point of tetraheadron is on wanted side of a plane?

wise pawn
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you could use the cross product

spiral gulch
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hi i am confused in one of my mock exam questions i dont really get it can someone help me?

upper karma
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use the basic formula

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sin²x+cos²x=1

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1-cos²x=(4/7)²

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1-cos²x= 16/49

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1-16/49=cos²x

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so cosx = 0.8206518066

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cotx = (cosx/sinx)

dark sparrow
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so cosx = 0.8206518066
ew

upper karma
#

yea i know

dark sparrow
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there is no need whatsoever to shove these ugly decimals in

upper karma
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it is squerooth of (33/49)

dark sparrow
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and also do not do other ppl's work for them

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and also it's square root

upper karma
#

bro i am dutch it is my phone his keyboard

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i try to help

dark sparrow
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please do not call me bro

upper karma
#

boy or girl?

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you dont have to answer

dark sparrow
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if you really care so much about a stranger's gender, then i'm a girl.

upper karma
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ok tha i take my words bro and so back

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sorry there is u shorter way

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so we now secx= (1/cosx)

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so secx= square root of (49/33)

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but tha is cot > 0 and it has to be <0

upper karma
#

0<cosx>1 so the corner is in quadrant 1

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and if -1<cosx>0 than is cotx<0

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so secx have to be -square root (49/33)

upper karma
lost gale
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does Diagonal in a rectangle across an angle?

upper karma
#

yes?

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what is your question?

radiant fractal
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hey quick question, is it no triangle because angle c gets cancelled or what exactly?

iron spoke
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side side angle

upper karma
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Ooooh yea

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There can be only one with ssa so 1 and 2 are false

silent plank
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There can be only one with ssa so 1 and 2 are false
bad reasoning

upper karma
#

you know something else

upper karma
silent plank
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i try not to give the whole answer away.

There can be only one with ssa
is false or incomplete

vagrant quail
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How do you motivate yourself to learn euclidean geometry at the Olympiad level? It just seems so unmotivated and dry

silk patio
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Motivation by beauty. What is the main motivation for you for any mathematics?

vagrant quail
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Well exactly, beauty. But there is barely any beauty in Olympiad geometry, cause all the problems always seem contrived or too niche to be relevant

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At least that is my impression of it

dark sparrow
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you're not alone in having that impression, if it's any consolation

vagrant quail
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Almost all the teachers that have taught me geometry just dump a load of theorems with no proof and then 2-3h of problems

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But I still believe that if I just learn it in the right way, I can see something in it

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Like Ceva's theorem

silk patio
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I wouldn’t let uninspiring teachers trick you into thinking the results aren’t beautiful or have no conceptual motivations

vagrant quail
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I do believe that the teachers are to blame in part for just lazily explaining the subject

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But is there an approach to this that doesn't feel like directionless gruntwork?

wise pawn
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what are you currently doing to learn euclidean geometry, what's your process?

twilit pagoda
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I started learning these trig functions a few days ago and I'm happy with my progression, I tried solving this problem myself but I'm getting a different answer than the lecturer I'm following.
So this is the question: https://snipboard.io/QCeA3g.jpg
And this is my solution: https://snipboard.io/KSB4tA.jpg
What wrong did I do there?
The lecturer used this cancelling technique which I'm not really aware of: https://snipboard.io/dcXQrW.jpg
And got this answer: sin x - cos x
However I'm getting cos x - sin x which is completely changing my final answer.
So whats wrong there?

Easy and free screenshot and image sharing - upload images online with print screen and paste, or drag and drop.

Easy and free screenshot and image sharing - upload images online with print screen and paste, or drag and drop.

Easy and free screenshot and image sharing - upload images online with print screen and paste, or drag and drop.

twilit pagoda
upper karma
runic dock
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@faint dagger

upper karma
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Is cot(-x) = -cot X?

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Or is that only in the case of sine?

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But sin(-x) = -sin X everywhere?

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And is that the case in any other trig fns

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here you can change this a in your x

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if you know the radials than you can use this

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pi is the same as 180°

wise pawn
upper karma
silk patio
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It’s cos/sin but doesn’t matter

upper breach
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can someone help me with t this

late thistle
cosmic smelt
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trad: calculate the volume of a parallelepiped with a square base and a diagonal of 26 cm and make an angle with the base of 53 °

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how do i graph that angle?

upper karma
#

What is it?

dark sparrow
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based on it being spammed all over, probably a scam.

upper karma
#

I think it

smoky palm
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Hey guys, look at this trig I learned

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Sin^2(x)+Cos^2(x)=cot^2(45)

humble pulsar
smoky palm
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Eh

humble pulsar
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since sin^2(x)cos^2(x) is a function dependent on x

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and cot^2(45) isnt

smoky palm
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What is cot*2(45)

humble pulsar
#

1

smoky palm
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I rest my case

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Shit

humble pulsar
#

You're still wrong

smoky palm
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I missed the plus sign

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There we go

humble pulsar
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yeah, that's just pythagorean identity

smoky palm
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That is

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On an not unrelated

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Which of the types of trig identities should be memorized?

humble pulsar
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I mean... hard to say b/c idk what your teacher would give you on a formula sheet

smoky palm
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I mean, for like

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Calc

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And

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Just, most of the general ones

humble pulsar
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pythagorean identity, double angle

smoky palm
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What about half angle

humble pulsar
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derived from double angle.

smoky palm
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Or the power something?

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I forgot the name of that one

humble pulsar
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then idk

smoky palm
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What about the sums and differences, or the ones derived from that

humble pulsar
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compound angle you should know, to which double and subsequently half angle come from them

smoky palm
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Thank you

humble pulsar
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as well as the "definition identities"

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like tan(x)=sin(x)/cos(x) and sec(x)=1/cos(x)

smoky palm
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The basic ones

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I didn’t know those were identities

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But, it makes sense

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Do I need to know how to use polar coordinates?

humble pulsar
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I mean for multi-var yes, but I never used polar in 1st year.

smoky palm
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When is multi var taught?

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Like, after what

humble pulsar
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2nd year.

smoky palm
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Do they do a review or something?

humble pulsar
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no fucking clue what the university you will go to will do

smoky palm
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That’s fair

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Sorry

wintry tundra
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@smoky palm the ones I use the most in derivatives is pythag and double angle

smoky palm
#

tyty

forest drift
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guys

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I proved ramanujan wrong again

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and that too 2 days before Indian Mathematics Day

upper karma
forest drift
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sum upto n natural numbers = n(n+1)/2

upper karma
#

are you trying to prove his statements?

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he is one of the biggest 'mathers' from the 20th century

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good luck with proving

forest drift
silent plank
#

sum upto n natural numbers = n(n+1)/2
how does that prove anyone wrong about anything

turbid star
#

that was from Gauss as far as I can remember

upper karma
turbid star
forest drift
forest drift
#

he told -1/12

turbid star
forest drift
#

I proved it is -1/8

turbid star
#

also, why is this in geo and trig

forest drift
#

come to prealg

upper karma
upper karma
turbid star
#

I haven't actually

#

but I heard that Mathologer got a lot of "hate" from that video

#

or it was something like that, I dont remember if it was Mathologer

upper karma
#

But he proved very efficiently every blunder ramanujan made

#

In sum upto inf = -1/12

wise pawn
#

you can only brag about it if you show it, otherwise you're trolling

forest drift
wise pawn
#

are you trying to imply this is some form of hate?

#

I'm just telling you your messages are not math and off topic here

turbid star
#

^^^

upper karma
#

Im 10 billion Percent sure sum of all natural numbers ≠ negative

forest drift
forest drift
weary drift
#

@forest drift ur whole history is trolling w/ poor attitude toward others. pls stop or face a ban

upper karma
weary drift
#

bye

upper karma
#

Shizz

#

@weary drift did you ban him?

weary drift
#

yes

upper karma
#

You shouldn't have

#

Can i dm because thats off topic?

#

aw man he was an entertainer

weary drift
#

i suggest not contacting him

turbid star
turbid star
weary drift
#

whole history was this. entertaining to some but in the end we dont want garbage contributors here

upper karma
turbid star
#

then later the cringe strikes back

upper karma
#

He was insecure to show prove because he was afraid they might steal it so he will only send it to the indian maths society (im concluding that because of his earliest chat here)

#

Agony of 9th graders are cringe indeed

turbid star
#

ANYHOW

#

off topic chat

upper karma
#

Oh btw are functions like sinh, cosh, considered trig?

turbid star
#

hyperbolic functions haha

#

i guess so?

#

not sure myself

weary drift
#

i think the enthusiasm for math is genuine. its just the approach to math & trash attitude

turbid star
#

yeah I agree

upper karma
#

Trigonometry
Measure of 3 sides (triangles)

Deals with circular function lol

#

And then we have hyperbolic function

turbid star
#

deals with hyperbola thingies

upper karma
#

Trig changed a lot haha

turbid star
#

wait that makes me wonder

#

do sech cosech etc also exist?

upper karma
#

We learnt it as triangles
Changed to circles
Evolved into have others

turbid star
#

im pretty sure they do

upper karma
turbid star
#

but how would they be defined

upper karma
#

Just like it is defined in normal trig

#

1/sinh = cosech

#

All that

turbid star
#

oh hmm

#

but geometrically?

upper karma
#

,w 1/sinh(x) === cosech(x)

#

Lol

somber coyoteBOT
upper karma
#

I have yet to learn conic sections

#

Im not even sure how they have defined sinh geometrically

#

I just know it as an exponential function

turbid star
#

like this

upper karma
#

Ahhhhh i see

#

But wait area is not dependent of theta i see

silk patio
#

It depends on it, just not linearly

bright cairn
#

A tangent to the ellipse x^2 + 4y^2 = 4 meets the ellipse x^2 + 2y^2 = 6 at P and Q. Prove that the tangents at P and Q will be at right angle

I tried using various method
lets there be a tangent at ellipse 1 - parametric
intersect it with e2
solve quadratic
but it got complicated
tried in reverse
and failed

#

oh

#

i am sorry

dull harness
#

Is anyone here

gleaming nova
#

we all just randomly pop into existence once someone has asked a question

#

so no

weak fjord
#

@gleaming nova

gleaming nova
#

why did you ping me

#

don’t ping specific people for help

weak fjord
#

cause u love math

gleaming nova
#

did i ask for you to ping me

weak fjord
#

my fault g 🚔 🚶‍♂️

#

aint know it was illegal

#

u dont gotta ask, its a feature for a reason, lmfao.

weary drift
#

@weak fjord pls dont ping randos

weak fjord
#

sure

#

I just seen him in every chat so I figured why not

gleaming nova
dark sparrow
gleaming nova
#

i feel like that same thing has happened to you as well ann lol

dark sparrow
#

sure has

#

many times at that

gleaming nova
#

the burden of being way too active

smoky palm
#

When do you start to use hyperbolic trig functions?

earnest basin
wintry tundra
#

Bc the derivatives and integrals for the basic h-trig stuff are the same

#

So its weird

silver willow
#

Should I talk about Analytic geometry here or in Pre-calculus?

smoky palm
#

For the half angle identities, are there third angle identities? Fourth angle? And if so, what are they?

dark sparrow
#

you can get something like a 1/4 angle identity by applying the half angle identity to itself

#

for 1/3 angles you would have to engage in cubic equation fuckery

dry basalt
#

They ask for the distance between the "source" (the red sun) passing through B to the "capteurs = sensors" (big blue arrow)
And they find this result:

#

I don't see how to get it, if a sympathetic soul can explain it to me. Thank you

humble pulsar
#

pythagorean theorem

#

the ray follows the 2 equal sides of an isoceles triangle

dry basalt
# humble pulsar pythagorean theorem

I don't see how you get this result with the pythagorean theorem, can you expand a little more please? How long are the sides of the triangle?

humble pulsar
#

The horizontal side is x

#

So drop a perpendicular from the reflection point to the horizontal side, you'll form a right triangle with legs e and x/2

#

Hence the hypotenuse cones from pythagorean

dry basalt
#

This triangle ?

humble pulsar
vapid terrace
#

I need to find 16 different and even distance from each other points on a circumference of a circle it has a radius of 3 (Unity measurements) how do I go about doing this I'm pretty confused?

covert dew
#

someone help me pls

woven copper
#

is there a way to add sinusoidal function without vectors?

covert dew
#

?

#

i’m not sure

mortal zealot
#

then no

#

that's the simplest form

covert dew
#

what can i do for an equation

#

to solve the problem

#

😣

woven copper
covert dew
#

??

mortal zealot
#

nope

#

You might be interested in this though

#

i hate this png

#

search up sum to product formulas

woven copper
#

like adding sin waves

upper karma
#

I wanna learn trigonometry

#

I have exam after two weeks

#

I need someone truely teach me

tidal drum
#

I'm trying to make a triangular tube 9" long. I'm putting a cylinder inside of it with diameter 4.375". at minimum, what are the lengths of the sides of the equilateral triangle?

#

I should be able to figure this out, I'm just... failing.

#

nevermind... google is my friend: Also the radius of Incircle of an equilateral triangle = (side of the equilateral triangle)/ 3. so that gives me the answer I need.

dark sparrow
#

that's not correct, or you may have mis-copied it

#

the ratio between the side length of an equilateral triangle and the radius of its inscribed circle is not 3

#

it's 2*sqrt(3)

#

@tidal drum

crude zenith
#

task is to find side of square

#

pls help

upper merlin
#

in words

#

for example what is that point hanging near the center of the square?

crude zenith
#

it is centre of square

upper merlin
tidal drum
shut finch
#

does anyone know how to work what is the distance from a to b

humble pulsar
#

are the square and circle concentric?

shut finch
humble pulsar
#

do they share a center Y or N?

shut finch
#

yes

humble pulsar
#

so find the radius of the circle

shut finch
#

that is the point how

humble pulsar
#

Hint: diameter of the circle and diagonal of the square are the same

shut finch
#

jesus christ(is king) wow how did i look past that thank you so much

#

@tidal drum

humble pulsar
#

then getting ab should be just line segment manipulation

shut finch
#

@humble pulsar

#

ok

candid sonnet
#

cud anyone please help me with this

upper karma
upper merlin
#

@upper karma he already got the solution

upper karma
#

ow i didnt see that

smoky palm
#

Are there any websites or anything that I can use to work on trig?

#

Like, the more advanced side to trig, with identities and whatnot, not just the right triangles

dark sparrow
#

<@&268886789983436800>

silk charm
#

thx

storm heath
#

What does produced to D mean?

#

Does it mean it is in the segment AB itself?

#

Or is that going away from the line?

nocturne remnant
#

I think D should be on the extended line AB but not segment AB
So from left to right the four points might look like A-C-B-D

storm heath
#

Is it like this?

#

Or this?

#

Or this?

smoky palm
#

I’ve got
cos(12)cos(24)cos(48)cos(96)

#

And I have to simplify it, what I did Is I know cos(18)

#

So, cos(30-18)=Cos30Cos12+Sin18Sin30
Then, do I just do some stuff with double angle identities to find the rest?

grave nova
#

How do I solve this?

#

Question 2 btw

humble pulsar
grave nova
#

???

humble pulsar
#

???

grave nova
#

What do you mean by similar triangles?

gleaming nova
#

same side ratios

#

one triangle is just a scaled up / scaled down version of the other

grave nova
#

Oh ok

brave needle
#

Is there a way to increase the period of sin(x) gradually

#

Kind of like sin(1/x)

wise pawn
#

is sin(x^2) sort of like you want

brave needle
#

Oh that’s good

#

But is it possible for the period to increase rather than decrease as x tends to inf

wise pawn
#

yeah, try to think in terms of what you're plugging in as hitting the multiples of pi less often

#

so like for instance y=x is not changing anything, but y=5ln(x) will be hitting them but less often because it's below y=x

#

so sin(5 ln(x)) will get something kind of like that

#

althought just a random choice of function that lies below y=x that's monotonically increasing

brave needle
upper blaze
#

Guys I found a claim on Wikipedia that there are 7 lines connected to tetraheadron that and concurent at its centroid. I know that one of them is generalization of Eulers line but does anyone have any idea what are other 6?

dark sparrow
#

can you link the wikipedia article that makes this claim?

valid osprey
#

\

upper blaze
# dark sparrow can you link the wikipedia article that makes this claim?

https://en.wikipedia.org/wiki/Euler_line
Under section "Generalization"

In geometry, the Euler line, named after Leonhard Euler (), is a line determined from any triangle that is not equilateral. It is a central line of the triangle, and it
passes through several important points determined from the triangle, including the orthocenter, the circumcenter, the centroid, the Exeter point and the center of the nine-point...

#

I mean this claim make a lot of things different but Idk what lines are they talking about. Though I am not suprised to see this. I myself found few lines that pass through centroid in my research though their importance to me is unknown (For my research they were useless)

#

And plus they dont seem like something that would be associated to tetrahedron in sentance like this.

grave pond
#

Seven lines that pass through the centroid of a tetrahedron would be the line from each vertex to the centroid of the opposite face, and the three lines that join centers of opposite edges.

#

(This is obviously the case in a regular tetrahedron, and any tetrahedron can be made regular by an affine transformation. Affine transformations preserve lines, planes, midpoints, centroids ...).

#

The Euler line analogue must be an eighth line.

upper blaze
#

Becouse when you say associated you just cant mean that becouse it is very well known

torn quail
#

hello, could anyone help me figure out how to calculate the surface area of this pot

torn quail
# torn quail

im not sure what shape to consider this part. a trapezoid?¿

upper blaze
#

Honestly, why do you think that you can apply math to concrete problem hahahaaha?

torn quail
#

lmao i have to

#

i need the surface area of this pot for an experiment im doing. it's relative to the cooling of water with varying s.a

upper blaze
#

Can you use aprox or it has to be accurate?

torn quail
#

as accurate as possible, as long as i can justify what im doing

#

im in high school so the procedure doesnt need to be very extensive

upper blaze
#

project it onto a plane?

torn quail
#

how would i do that? loggerpro?

upper blaze
#

and assume all are straight lines?

#

Well projection will be close(if not accurate) circle so you can take paper and wrap around it to get diameter of bigger one

#

or radius whatever

#

radius of bottom part(small cirlce) you can measure when you find center using normal geometry

#

rest of it should be easy assuming all are lines and curvature you throw away and say its an error

torn quail
#

but isnt the curvature important tho

#

wait so basically what you're saying is to ignore the curvature in this part and consider it to be a large flat circle?

upper blaze
#

assuming they are straight lines

torn quail
#

oh okay thanks

upper blaze
#

Or

#

ORRR

torn quail
#

ill have to ask my supervisor if i can ignore the curvature lmao

#

mhm?

upper blaze
#

well you can use thee meter thats used for measuring cloaths?

#

to find exact measures

#

But again some aprox should be made

torn quail
#

wait that's not too bad

#

a measuring tape could work

upper blaze
#

Hmmm I am not sure actualy maybe you can measure those 2 radis I told you and that height difference of those 2 circles and then

#

oh wait actually maybe you can do it precisly but it will take some work if its possible at all xD

#

I am thinking that you can find surface that contains that part in between the circles

#

I mean its equation

#

using geogebra or something

#

But hmmm

#

I dont know hahahah

#

really I dont know

clever fable
#

Do vertical asymptotes of a function become a 'hole' when we take the function's reciprocal and graph them?

#

Or will that depend on the function that we are taking the reciprocal of?

humble pulsar
#

since you'd have the reciprocal of (not 0 number)/0 becomes 0/(not 0 number), which is 0

pliant jasper
somber coyoteBOT
clever fable
#

^^^^

humble pulsar
#

In that case any function has a hole

#

which is absurd

#

cause it's not true

#

the reciprocal of 1/x is x

#

x is continuous on R.

pliant jasper
#

Ok 👍

clever fable
humble pulsar
#

yes that still has problems

#

and no, it wouldnt

clever fable
#

oh

humble pulsar
#

log(0) is undefined

clever fable
#

Ok I think I kind of understand, it will just be a root then right?

humble pulsar
#

no.

clever fable
#

how would the graph look like?

humble pulsar
#

x=-1 isn't in the domain of either log(x+1) or 1/log(x+1)

#

,w graph y=1/log_10(x+1)

somber coyoteBOT
clever fable
#

Wait so what's happening at x = -1, if it's not a root?

humble pulsar
#

not going into the in-depth analysis rn, cba

#

my guess is just approaching in the limit

clever fable
#

hmm I see, it's just in my teachers' solutions, there was a hole, and I was just confused because I thought all vertical asymptotes are going to have holes - which i have realised is now not the case

#

Thanks for bothering anyway XD!

humble pulsar
#

Yeah holes and asymptotes are completely different

#

it approaches the point (-1,0) from the bottom though

clever fable
#

Yea it makes a bit more sense now (I think). I'll probably just check the solutions with my teach, but it seems more clearer (in terms of what's happening when we take the reciprocal of the functions.)

hoary mango
#

what the fuck is with pythagorean theorem 💀

#

can't even get sides correctly

spiral mesa
#

Wdym

hoary mango
#

i keep squaring at wrong sides

#

like

#

i could be trying to solve a right triangle

#

and my deadass would square the hypotenuse

#

to the a or b side

spiral mesa
#

Just beware the location of the right angle and that's it

#

I was about to type angel instead of angle lol

hoary mango
#

i've bewared a fuck ton of times

#

but i still get it wrong

#

turns out hypotenuses arent always diagonal

gleaming nova
#

the hypotenuse is the longest side of a right triangle

#

or just the side opposite to the right angle

upper karma
#

both

hoary mango
#

i know what a hypotenuse is

#

im just saying it's not always a diagonal line

silent plank
#

how is a line being diagonal relevant

hoary mango
#

😐

#

have you not heard of the past messages i made

#

i said a fucking hypotenuse isn't always diagonal

silent plank
#

wdym by isn't always "diagonal"

hoary mango
#

like

#

hypotenuses could be anything

#

but diagonal angles aren't always the longest

silent plank
#

if your trying to identify the hyp by whether a line is "diagonal," then that's the source of your problem

#

the hyp is the side opposite the right angle of a right triangle

#

diagonal is also vague in this context and I have nfi what you actually mean by that

dark sparrow
#

it's something that depends on the orientation of the triangle as drawn on the page

hoary mango
#

see

#

its not that fucking hard to know what i fucking mean

silent plank
#

is the swearing necessary?

#

if as drawn on the page, no lines are vertical/horizontal meaning you'd consider all your lines to be "diagonal", then you're stuffed

chilly whale
hoary mango
#

why do people take this so personally

chilly whale
#

Who?

hoary mango
#

the fact i said diagonals arent always the longest

chilly whale
#

Not sure how that has any relevancy for why people should take it personal, which I'm pretty sure no one is doing.. It's more or less just surprising that you're defining diagonals that way.

silent plank
#

tbf i took it a little personally when swearing was involved and the implication that i was illiterate

chilly whale
#

^ that I can understand. People that ask for help are not even trying anymore

grave pond
#

Manners aside, in the diagram in Euclid's proof, the hypotenuse is horizontal.

glacial dawn
#

He’s a mobile Roblox player

weary drift
#

@hoary mango curb ur attitude

versed valve
#

Hey can you help me on how do i prove the reflective faculty of hyperbola and ellipse?

opaque gull
vital moat
#

I've been struggling in advanced functions a lot and got a 53 and 58 on the first 2 unit tests, does anyone know how I could convince my teacher to assign me mark boosting work?

viscid crag
#

hi !

#

opps sorry, wrng grou

royal raptor
#

Can anyone solve this problem or is it too Hard?

humble pulsar
#

<@&268886789983436800>

clear haven
#

band

quasi matrix
#

hey

flint wyvern
#

If I have a circle centered at (4,4) with radius 2, what are the functions of the two tangent lines to the circle passing through (0,0)?

#

Just playing around with this for a LaTeX illustration I'm making... can't seem to get it !!

dark sparrow
flint wyvern
#

he means he got a 53% and a 58% as two separate grades

#

which in the states, if repeated on a sufficient number of exams, will force the student to retake the class

dark sparrow
#

...i could have sworn the message said "53/58" with a slash the forest time i read it lol

empty kite
#

I'm having a bit of trouble w' this question

silent plank
#

what did you discover in Q16

empty kite
#

The thing is

#

I don't know

#

There was no q16

#

Teacher just posted this in teams

#

+bunch of other questions asked us to solve as review for finals

silent plank
#

you could start by drawing in the centre, radii to the points of tangency and denote the length as r

empty kite
#

Sorry I still don't get it

silent plank
#

which part of that don't you get

empty kite
#

I don't understand what's next...

silent plank
#

did you do what I recommended?

empty kite
#

Am I supposed to see something

silent plank
#

that doesn't answer my question

empty kite
#

Yes

silent plank
#

making those constructions might not lead you directly to the answer you seek, but they will most likely be helpful

empty kite
#

Hm

dark sparrow
#

can you show us what your diagram looks like after doing what ramonov instructed you to do?

silent plank
#

(note these initial steps are intended to help prove the implied result from Q16)

empty kite
#

Hold on

graceful ginkgo
#

You can try drawing squares inside the circle to solve it

lusty abyss
#

Help

dark sparrow
#

what is troubling you here?

#

@lusty abyss

#

is it ||that the problem presents an obviously impossible scenario||?

lusty abyss
#

Yes

lusty abyss
silent plank
#

as shown, the scenario as shown is ||impossible|| and it is pointless to continue

lusty abyss
#

Why would someone give something like this to a grade 7 kid

dark sparrow
#

incompetent or inattentive teachers,

#

or perhaps incompetent board members who overlooked this glaring error

iron spoke
#

how are you even supposed to solve that

#

with 0 info

silk patio
#

What do you mean it’s impossible

grave pond
#

There are at least two ways.

silk patio
#

Calculate the area in two ways

grave pond
#

The altitude from P is supposed to be longer than either PQ or PR.

#

The altitude from Q is drawn inside triangle even through 5²+6²<8² so the angle at P must be obtuse.

silk patio
#

This is megahyperbolic-geometry tho

#

It’s a shut up and calculate moment

grave pond
#

What stuck me first was that they say "QY = x; find the value of x" instead of simply "find QY", but that strange phrasing fades into the background once it turns out that the diagram is impossible anyway.

#

Even if it is hyperbolic geometry, both of my objections would still apply. (And the Euclidean area formula won't work there anyway).

dark sparrow
silk patio
#

Megahyperbolic-geometry

dark sparrow
#

what the fuck is that

silk patio
#

A joke that you took seriously

dark sparrow
#

this is no place for jokes

#

your objection appeared genuine. you cannot accuse me of taking your joke seriously when you present it as if it were serious.

silk patio
#

Don’t blame the fact you didn’t pick up on the social cue on me

dark sparrow
#

what social cue

silk patio
#

Exactly

dark sparrow
#

are you in all seriousness saying that i should have picked up on a social cue that wasn't there?

silk patio
#

It was there, you just missed it. It’s okay

grave pond
#

Just ignore him, he seems ot be a troll.

dark sparrow
#

i asked you

#

"what social cue"

#

and you refused to answer

silk patio
#

Yeah you’re right, I’ll ignore them

junior light
#

I request both of you to de-escalate.

silk patio
#

Haha, yeah I think it’s over

#

All in jest

dark sparrow
chilly whale
chilly whale
#

And what the people have mentioned above of course!

pastel fog
#

I have a question, I stumbled upon an interesting post by Andy Sloane, the post is about Rendering a 3D ASCII donut on a 2D plane, his blog post Andy defines the math behind it. But I am quiet stuck somewhere.

The points (x, y, z) is defined by the expression (R2,0,0)+(R1cosθ,R1sinθ,0) I do not get how this was derived.

The blog post link is here: https://www.a1k0n.net/2011/07/20/donut-math.html

grave pond
#

(R2,0,0) is the center of the circle. The added term R1(cos theta,sin theta,0) is the standard parameterization of a circle in the xy-plane.

pastel fog
#

Thank you @grave pond 🙂

upper merlin
#

I found all the trivial angles but it just seems impossible to get to the solution

hoary mango
#

bro how the fuck do i do unit circles

#

it literally never indicates any point at any time

hoary mango
#

how the fuck do you get 170 on this

spiral mesa
#

Cancel out 180 with 18 and pi with pi, so you get 10*17

hoary mango
#

nah trigonometry is fucking mid

#

functions are literally like 100x better than this crappy ass course bro

spiral mesa
#

What's so terrible about it

hoary mango
#

the fact it has so much out of context equations

#

and then it just turns into an AP for no reason at the math part

#

i feel like precalculus should be a better choice than this since its functions and shit like that

#

while in trigonometry, you get stupid equations with stupid formulas

#

like literally

#

they dont give steps on how they got their first answer

#

they just skip it off, leaving questions to the fucking void

#

so overall, trigonometry sucks and it always will

#

once bad, always bad

iron spoke
#

nah bro they just taught you trig in the worst way possible

upper karma
upper merlin
#

gotta learn this trig way of solving

#

I found a pure geometry solution later tho

short arch
#

Hi everyone, I am at 11th grade, and I am learning the cross product, is this solution correct?

dark sparrow
#

you will have to show us the problem you're solving

#

@short arch

short arch
#

I am still practicing this method, I am asking if I did it correct or not despite the problem, did I apply the right hand rule correctly or not?

dark sparrow
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,rccw

somber coyoteBOT
dark sparrow
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ok so you're just calculating the cross product of A and B

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the sketch looks... adequate i guess

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the way you drew C it looks like it's pointing in roughly the right direction

short arch
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So I did it correct?

dark sparrow
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i guess so?

short arch
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Thanks for your help

dark sparrow
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but you haven't shown what the value of A×B is

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and you've also omitted the length symbol in the last line

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and also i guess you got this angle of 22° out of nowhere

short arch
dark sparrow
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oh, you assumed it? why not assume it's 42.069 degrees exactly?!

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why not assume that 2+2=5 while you're at it?

short arch
iron spoke
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i think she was joking lol

graceful halo
upper merlin
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I have no clue how I got this

river marsh
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Just posting this here even though I’ve got a help channel open, just because it’s been open for quite a while without a response. This is a year 1 university problem but none of the early uni channels seem to fit this question

Is the sum of the forces in each cable equal to the weight of the plate? And if so, how do I solve that algebraically? Preferably using Cartesian coordinates

upper karma
mild birch
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all the horizontal vectors/ ones on the plane cancel each other out

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vertical ones add up to give the magnitude of weight

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you’ve got T1x+T2x+T3x = 0

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T1y+T2y+T3y=0

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T1z+T2z+T3z = mg

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it’s basic trig to see what T1x or wtv is

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@river marsh

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i hope that made sense

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then it’s just simultaneous eqns

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if you’ve got a calculator that does matrices, use it, it makes your life easier

river marsh
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my calc can do simul. equations

mild birch
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oh, that works too

river marsh
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i think i may have thought about this too deeply

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because i was resolving the forces into cartesian vectors i,j,k and then trying to figure out the tension

mild birch
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ahh well, i remember doing 2d ones in school, wasn’t too hard to extend it to 3d

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you could , but do you need to ?

river marsh
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well i must have gone wrong there because i got dumb numbers

mild birch
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t look like bunch of points