#geometry-and-trigonometry
1 messages · Page 365 of 1
Help pls, with the process
that’s an exam right
Hey, I have made a video on a "Secret Proof for Pythagoras Theorem". I think you all will throughly enjoy it. Should I share it here?
Pythagoras Theorem is the most popular theorem that math has to offer. But most can not appreciate it's beauty, subtleness, and wide spread usage. This video will help you prove why Pythagoras Theorem is true in the best way possible. Weekly Newsletter: https://brainspoof.mailchimpsites.com/
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References
Elements of G...
sin^2x = 2sinxcosx
is this correct?
Mosh
what's
sinx . cosx = m
what?
sinx . cosx = m
what's [sinx - conx]
the absolute value
I hope that's what it's called in eng
sinx . cosx = m
what's [sinx - conx](absolute value)
?????
I have no clue what you just typed
still?
nope
what's wrong with it
peaceGiant
help me with something in geometry guys it is posted in question 3
please please
@wanton portal
can someone explain to me how tan(1) = is pi/2
like if tan = sinx/cosx
so then sin1/cos1, (pi/2)/0
undefined
what are you talking about???
sin(1) isn't pi/2 and cos(1) isn't 0...
and tan(1) isn't pi/2
,calc tan(1)
Result:
1.5574077246549
,calc pi/2
Result:
1.5707963267949
no.
is that not how that works or what
it's sin(pi/2) = 1
oh ok
the input of sin, cos, tan, etc. is the angle
so how am i supposed to find the value of sin(1)
yes i am
what?
arctan(1) is way different
how so
well for starters this is an inverse trig function
arctan(1) is the solution of tan(θ) = 1
(subject to some restrictions on θ to make sure there's no ambiguity)
just learned the unit circle 2 weeks ago
halfway thru calc 1
lol
but that's the least of my worries
It basically is
Ur just biased
I'm being 100% /srs
really?
@wintry tundra pls don't shitpost here
Fine

hey, I was just wondering, why is there two thetas, in the triangle here
shouldn't it be pi/2 - theta, (for the point M)
(or is it just a mistake they made?)
your angle is always taken from the x axis, not the y
no, it is not wrong
pi/2 is the y axis, so if you did pi/2-theta, you'd be taking an angle from the y axis
angles are taken from the x axis
hey, seems like c and d inversely proportional in the f(x)= a.cos(cx + d) + b function but i don't get why
In the graph, the coefficient c is setting the amplitude and d is setting the translation, but the translations of d are affected by the coefficient c in the coordinate system. In a inversed proportial-->
cos(2x + 1) + 6 and cos(x + 1)
cos(2x + 2) + 6 and cos(x + 2)
cos(2x + 1) to cos(2x + 2) delayed 1/2 unit but why not 1 unit is what i'm asking
tbh, d is not the translation in the x axis
the translation in the x-axis is d/c
which way?, that depends on the sign
and c and d are not inversely proportional to each other
and that above, just answered why
what have you tried?
you have used the wrong sides
you have to understand that the general volume formula for prisms is B*H where B represents the area of the base and H represents the height of prism extending from the base
now from that formula, we achieve the formula bhl/2 for triangular prism
where b is one of the side of the triangle base, h is the length of the altitude to that side aka the height of the triangle, and l is the length from the base
lemme just name some stuff first so its not vaguely describe
alright, so in this case, what you need is the area of the triangle
which is basically AB*BC/2, since this is a right triangle at B
well, one could argue that you can draw an altitude from B to AC
and yes, i agree, you can, but why make it hard when you have the easy way
so you just need BC, which is pretty straight-foward to find
so to conclude:
Base=AB (or BC)
Height=BC (or AB)
Length=BB'
so finding BC using pythagoras theorem was a coincidence then I guess.
That's truee
i never said it was false, and i have explained where and what the formula means
again i have listed out what should do
it seems like you are not reading any of my message
how to find BC?
pythagorean
or if you want to do it the hard way and find the altitude from B to AC then also pythag
yeah that works but it says nothing about a right angle or B to AC will be a median
so if it's not 90 degrees we can not use pythagoras
yes
so whats BC
if the information right triangular prism is not given then not enough information is given
use pythag?
oh i just realised i read the question wrong
yeah, then not enough information is given then, we would need at least an angle or another side
How to find vector PQ in terms of vector AD and vector AB
i have found :
5/7 AD - 4/5 AB
Is this correct?
So, your angle is theta, so that's the angle you'll be working off for each triangle. For example, on Triangle 1, opposite theta is 8 and adjacent is 6. What angle uses Opposite and Adjacent?
I'm having some trouble here with this first problem. I'm not the best at logic stuff like this. (Also the Coliseum window is just a room with a long window on one end of it.)
I have a graph too if it helps any.
Like you're not standing outside since you're at y<0, you're above ground since z>0 and you're just standing 2 meters to the right for the x. Right?
It's a right triangle, so one side is the diameter
<@&286206848099549185>
Hey ya'll 🙂
I'm in a trig class, I like trig, im happy to do the work. I have been struggling understanding Trig concepts and I think it is because it is all lacking human interaction. Anyone care to review some trig topics with me? I have a test in 10 days = /
do you know how to solve trig equations
also, do you know how to solve trigonometric proofs
and finally trig word problems
know all your double angle formulas, and trig identities
cirumscribed means that the triangle is in the circle
hOW
are the designs made on table or cloth? but the cloth is hexagonal
qn is not clear enough but it seems like the design is the part on the table that the hexagon doesn’t cover
like the area of table under hexagonal cover isn't designed?
i think no that’s why the hexagon is there to cover the rest of the table
dude this question
this qn is very unclear
i Haven't seen such table tbh
@hoary rover what in the fuck
What math are you in?
Like is this a high school geo?
Wow, I'm not familiar with the [ABCD] notation. Is that an area or perimeter?
area
Just assume ABCD is a square 
there's so much here it's like intending to throw students off
it's an exercise in willpower
idk actually maybe they really want you to remember all the notation
Do you still need help? I got an answer 30.
Hello, could someone help me solve this problem:
In quadrilateral ABCD, P and Q, are the midpoints of opposite sides AB and CD. The point M is the midpoint of BCD and N is the midpoint of PQ. Prove that the points A M and N lie on the same line.
I think it should look something like this:
C does not always have to lie on the line ANM
but in any case, ||Menelaus’ on BPQ should work||
Im late to the party ik
Ahaha you use geogebra
Great app, I use it all the time
Lol yeah
the work is messy but you'd need to determine the area of the base triangle (which is implied to be a right triangle)
which can be achieved by first determining the length of the unmarked leg using pythagoras
what d you find confusing i will try and help
OK you have to work out the sides of the triangle and use them in your formula
note that 10ft is the length of the hypotenuse and is NOT the height of the triangle
Exactly Romanov
the work is messy but you'd need to determine the area of the base triangle (which is implied to be a right triangle)
which can be achieved by first determining the length of the unmarked leg using pythagoras
Four circles are drawn, with the centre on the verticies of square... Each circle touches the boundaries of two other circles out of four.
How are their areas equal??
doesn't really matter than much
if you consider 6 to be your base, 8 will be the height
and vice versa (you can consider 8 to be the base and 6 to be the height)
either way you'll have 1/2 * 6 * 8 or 1/2 * 8 * 6 which has the same value
(which is implied to be a right triangle)
which can be achieved by first determining the length of the unmarked leg using pythagoras
I'm not sure that they have to have the same area to satisfy these conditions...
Neat. So blue circles (every other) can vary in s/2 <= r_blue <= s/sqrt(2), as s/2 <= r_red <= s(1-1/sqrt(2)) ?
Doesn't that disprove the premise that they are all the same?
*same area
Yea I guess, since the radius of the circles varies...
Varies from (√√2)/2 to 2-(√√2)/2
Although I just did (√√2)/2 to 1 as demonstration
And of course you can prove it algebraically
i mean can you put it in simple terms
can I make 4 circles, centred on verticies of a square and each touching the other two, which are not equal in radius and, hence, area?
so whats the justification or reason for these circles having equal area
They don't all have equal area. Please state the problem exactly as it was given to you. If you have, the claim that all circles have equal area isn't always true under the required conditions (that all circles are tangent to two circles).
however, circles in opposite corners do seem to be guaranteed to have equal area.
Area depends entirely on the radius (A=pi*r^2).
Question: the figure, ABCD is a square of side 14 cm. With centres A, B, C and D, four circles are drawn such that each circle touch externally two of the remaining three circles. Find the area of the shaded region (area in the square not occupied by any circle)
Is there a picture we can refer to?
blue
they reject that only opposite ones can be equal
and take the second one where all r equal
From my example, I used square of side length 2, then the "shaded area" will be
2²-(r²+(2-r)²)π/2
Where r in a real number between 2^(¼)/2 and 2-(2^(¼)/2)
If it's just the case, then it's not hard.
Since it's some fixed graph and not moving ones.
it's not animated I guess because there are two parameters...dumb
@dusky surge you know how to make the second slider animate?
does the side length need to be constant? that would be a shame
Haha I don't know how to make 2 slider animated
yo can someone hop on call with me i got a problem solving arccsc(sec2pi/3)
ooh! me
Dunno lol, I don't really know how to use Desmos
ok, well that's less interesting.
you have 4 quarters of equal-sized circles being removed from the square region.
The radius of each circle is half of the side length.
So the radius of each circle is 7.
The Area of each circle is what?
If you have 4 quarters, that's a whole circle being subtracted from the square's area, right?
In 2D space, yes
In 3D space, not necessarily. It can be mapped onto itself. It depends on where the line is rotated about
So we know that the formula for the circumference (the base of a cylinder is a circle, and the perimeter of a circle is the circumference) is (2)(pi)(r)
Yea?
Yes we can also use that formula as well
And since we are using pi = 3, let’s change the formula to (2)(3)(r),
So you got it?
Or…
Ok so
Right we are going to get there in a moment
So the formula in this case is C = (2)(3)(r)
C being the circumference
And since we’ve already been the circumference, which is 24, we plug it in
24 = (2)(3)(r)
Since the circumference is the perimeter of a circle
And a cylinder’s base is always a circle
Yep
24 = (2)(3)(r)
It’s a simple equation from there
Just solve for r
Yea for sure
It’s just we need to convert the d into r later on
So the formula now is C = (3)(d)
Yep
Then we just solve for d
Yep
Perfect
I mean we could use the process of elimination here
Or we can check mathematically
F would be 25/12
2.0833
Yep
Since we rounded down pi from before
So they rounded up the final answer
Hmm I mean that just depends on the question
If it asks you to round to the nearest tenth then that’s what you should do
I feel like the book your using shouldn’t have done that
It’ll likely be more specific in exams and tests
No problem have a good night/day
the radius isn't always half the side length
as per this
Then the area is not fixed.
so then we can't find the shaded area?
We can.
This
Or for your case
14²-(r²+(14-r)²)π/2
Where r is the changing radius or one of the pair of circles.
His problem statement implies it is. We wrestled with that part already, they just want the case shown in the picture their teacher gave
well i guess I'll have to stick to the radius being equal case
it makes it easy and i get the answer
and marks lol
Lol, I think that's what they want
shouldn't the answer be 196 - 4 [(Pi*7^2)/4] ?
so basically the answer should be 42 Cm^2
yes
unless the radii are allowed to vary
but your picture and description pointing to the picture implied they weren't supposed to
i didnt share any picture , you got me confused with someone else
yeah, I was just telling my boi @dusky surge about that
Kek
But I wasn't refering to a person
just the picture
was this your problem?
thought it was theirs
😂 you guys got confused a simple question with a complex one
@neat stag
but how do you solve the complex type ?
complex meaning....?
in which the radii may vary
You can scroll all the way up~
the complicated one?
yes
ok
yes
there are two pairs with radii that have one value, and two pairs with a complimentary value
the sum of the radii must equal the side length of the square
so you can just subtract half-times the area for both cases from the area of the square whose area is (2s)^2 (if you're going by how I put it in Desmos)
ok thanks
let $s$ be half the side length of a square and choose r such that $$r \ni [s(2-\sqrt{2}),s\sqrt{2}]$$
un-simplified:
$$A = (2s)^2 - \frac{1}{2}\pi r^2 - \frac{1}{2}\pi(2s-r)^2$$
Disorganized
$$A(s,r) = 4s^2 -2s\pi(r - s)$$
how do I solve this
Disorganized
you rationalise
...maybe, don't trust me this early, or that late
how
so basically multiply sinx/cosx+1 with cosx-1
wait
@upper karma please confirm what the expression in the denominator is
I don't get what you said
i also have a doubt lemme share it
2sec^2 theta - sec^4 theta - 2cos e * c ^ 2 * theta + cos e * c ^ 4 * theta = cot^4 theta - tan^4 i
is your expression
this
yes
$\frac{\sin{x}}{1+\cos{x}} + \frac{1}{\tan{x}}$?
Disorganized
they want me to make it the simpliest
solve this also , its a solved example in my textbook yet i dont understand the final steps
just write $\tan{x}$ as $\frac{\sin{x}}{\cos{x}}$ to start
Disorganized
did we do
1/tan > 1/sin/cos or cos/sin ?
(cosx)(sinx)/[(cosx)(1+cosx)] + (1+cosx)/[(cosx)(1+cosx)]
tanx = sinx/cosx
so if it's on the bottom of 1, that is, 1/tanx, that's 1/(sinx/cosx) = cosx/sinx
1/tan > 1/sin/cos or cos/sin ?
I dont have a memory for this
Sexy
Are you sure you typed that as it was given to you?
meaning ?
yea , i used google lens and then pasted here
it has some typos and it's not clear what goes with what
and I know typos very well
maybe take a screenshot
or use LaTeX
how do i use it
Hmmm... Can it be shown like... A picture? All I can see is a downloadable file
how do i do that
Use the camera?
i was on my laptop
Lol the Google lens got cos(e*c)
yea XD
Okay, on my first thought
I think you can group
First 2 terms together and of course, the last 2 terms together
@dusky surge if you were bri'sh would you be known as crumpet
how do i do that ?
Kek
ok i get it now
Like since they have a factor
sec²θ in common
that step is given in the solved example but then they add 1 to both the groups for some reason
yea
Wow that's a nice move
What did I do wrong?
wait
This is so painful
like whaat
I'll come back later
RHS in step 4 is wrong
Ok
also your notation for multiplying top and bottom by something, I've never seen that before. You followed through with it on the left but messed it up on the right in step 4. Maybe just write it out
"say what you mean"
pretend you are teaching someone else what you are doing
@winter pumice xplain this please
that was brilliant until the last step
they are separating the sec(x) and csc(x) parts and anticipating a polynomial perfect square trinomial form
both polys are of the form x^2 - 2x + 1
they were just missing the 1's
oh now i see
the 1's they appended will cancel
so basically of the form ax^2 + bx + c
more specific then that, but yeah
this was very helpful thanks
they were going for a perfect square trinomial
analogous to x^2 - 2x + 1 = (x - 1)^2
if you let x=t^2, you can see it still works
t^4 - 2(t^2) + 1 = (t^2 - 1)^2
you can also do it with trig function substitutions. They had x= [csc(theta)]^2 in the first one and x = [sec(theta)]^2 in the second
no, I learned this in highschool just like you
but I've been doing this for about 15 years longer
oh much appreciated man
Is this correct? It feels wrong for the area to go to infinity when the angle goes to zero.
How did you derive A = br/2? That isn't the area of the arc sector
Oh, got it. It can be obtained by multiplying the very first equality with r/2.
When alpha is really small, you have this really long radius*. As alpha tends to zero, r will tend to infinity. So the area might be pretty large.
what's trigonometry?
if sin0= 1 then its not trignometry
- what are the identities you wrote on the RHS
cotangent 2a
2 cotangent a
did your teacher tell you to write cotangent like that?
Because that is the second really unusual writing of a trig identity I have seen in 24 hours
Yes, we have these in all textbooks
are you sure
Disorganized
Yes
Disorganized
We have Russian textbooks, we write tangent and cotangent - tg, ctg
Ah!
ok
Ok so you remember how there are laws of exponents and logarithms?
there's a really long version of that for trigonometric identities.
"trigonometric identities". Usually if you search that, you get a short list. But sometimes you get longer lists.
First one might require the product formulas for sine and cosine
let me look at it a min
*let me try it
Solved part A by reorganizing top and bottom, using sum-to-product identities.
Cosine is an even function so it didnt matter how I ordered the first 2 terms in top and bottom when I used the identities.
how much trig have you learned?
have you learned about sine,cosine,tan yet?
ok
which trig function do you think would be most useful here?
no
relative to the 67° angle,
can you identify the position of the side x
no
Romanov can I also help please
the side x isn't touching the 67° angle
Yes sir
yes x is opposite the 67° angle
can you identify the position of the 2m side relative to the 67° angle
yes
so you have the angle, the opp and the adj
yes
Yeah you would do tan(67) /2 ?
Yh
Yeah I’m pretty sure you do tan(67)/2
Since toa
You put it in brackets on the calculator
how do you calulate trignometric thetas for various angles
for now i just memorised trig ratios for 0, 30 , 60 and 90
for example how do i calculate the value of tan67 deg ?
put it in a calculator
i could but when i don't have calculator sitting around ?
you could do a taylor expansion if you really want
wouldn't be fun though
and it wouldn't be exact
yes
depends
but normally if i'm not allowed a calculator on an exam, the exam doesn't need a calculator
i see
they use easy numbers that i can work by hand, the exam is more of a test of concept
understandable
so what i understand up until this point , there are like 5 strategies to prove trignometric identities -
1direct identity use
2 lcm
3 convert into sin and cos
4 rationalise ( only works for sin and cos)
5 using polynomial identities
can anything be added or corrected ?
haven't proved trig identities in a bit, but seems about right
factoring is also useful
whats factoring ?
$x^2-4=(x+2)(x-2)$
a disappointing son
oh yes
$x^3-3x^2+2x=x(x^2-3x+2)$
a disappointing son
👍
what's your issue with this?
i have serveral questions i need help with tho
Can someone explain to me why that is the period
<@&286206848099549185>
Isn't finding the period 2pi/b
and not pi/b
why is that saying pi/(1/2)
pls ping me
Hey! Can someone help me with this: A square ABCD is given. Points P and Q are taken on the sides AB and BC such that the BP is equal to the BQ.BH is the height of the triangle BPC. Find the angle DHQ
Unclear where H is.
h is on CP
Please screenshot the problem so we get the original statement and any figures it refers to
Put it up here so everyone can refer to it
...until it gets buried over the next few days
Since Discord 'forums' move quick
but the problem is not in english
Bulgarian
Can you copy-paste the text?
no
can you help me with the problem
I probably have to translate it first, but maybe I dont, depends
You can translate it. Replace every instance of a string of letters with the Bulgarian word for something else. Pie, maybe (the pastry, not the number), run it through Google Translate, and then bacl-substitute the strings of letters
Please put the screenshit up though so we can compare it
Ok, how about this: is H an intersection point?
Can you just draw the figure
Because the description sounds good until H comes out of nowhere
@neon grotto
give me a second
i have written on the paper sorry
@winter pumice is it good now?
@neon grotto I suspect that tri HBC is similar to tri HCD
i dont think so
By the way dont continue torturing yourself i think i solved the problem!
Oh good
Thank you for your time and help
What did you get?
angle dhq is 90 degrees
Wow, really?
Ok, bye
have a wonderful day
fish
Maybe try draw it i cant help you now cuz im in a car
Oops I mixed up B and A
But notice that the 2 similar triangles must both contain theta and 180-theta
Which is not normally possible (as the remaining angle would be 0)
Unless…UNLESS!
theta = 180-theta
So that gives theta = 90
I dont know where to post this but can somoene please tell me how to get the bisector of a line pls ping if you want to send a solution cause i have a maths test tomorrow
Thanks elon
imma have to review this
cos means cosine.
The area of trapezium ACFD is the sum of the areas of tri ACD and tri CDF
We know that AC and DF are parallel because the planes they are in are parallel, and they are hypotenuses of similar triangles (tri ABC and tri DEF by SAS-similarity).
This means trapezium ACFD is a plane figure
This is why we know we can add the triangle areas we picked: it wont matter how we cut the trapezium up because all its points are coplanar
(Somebody pop in here and tell me every "trapezium" is a plane figure)
Anyway. Should be easy for you to take it from there, calculating the areas of the triangles in the trapezium, because they are right triangles as well (justify this!) and you can get their side lengths easily. Let me know if you get stuck.
I have not written anything down to figure out this will work, try again following the steps I described
Ok, what are the side lengths of ABC and DEF
I cant figure it out
^ you dont know how to solve a right triangle given 2 of the 3 sides?
½bxh?
Thats an area formula
oh
What formula gives you the sides of a right triangle
no clue
Get a clue then: Google it
pythagoureous ?
Yes
Yes
You only need the 2 formulas you listed to solve the problem
Plus a little logic
Ok
(DE)^2 + (EF)^2 = (DF)^2
So then
(6)^2 + (6)^2 = (DF)^2
36 + 36 = (DF)^2
72 = (DF)^2
what next?
find out Df?
How
idk
What is the inverse of squaring an unknown?
*what is the inverse of squaring something
I not even onto pythagorous yet
Shen
Just be careful with signs.
Thanks Shen, for confusing me with OP
But I guess its good the definition is here now
Nah, its good, it's pretty
Thanks 😅
Wasn't sure if I should delete it because you're trying to get him to think about it
Respect 👊
Did your teacher give you this problem?
Did you cover the distance formula yet?
yes
That's a form of Pythagorus. You guys have covered this
It would have come up by now
oh then no
You already listed the formula for Pythagoras, are you saying you don't know how and have never taken a square root?
Taking a square root is an inverse operation to squaring
If you take the square root of x^2, you get x again
yes ik
...because they are inverse-operations
This is the way I like to explain it:
x | x^2
1 | 1
2 | 4
3 | 9
4 | 16
5 | 25
6 | 36
When we square the input x, we are doing x*x
So we go from the left column entry to the right column entry
$\sqrt{x}$
Disorganized
is a function that can take us from an entry in the right column BACK to the entry in the left
It tells you what number got squared
So $\sqrt{36}=\sqrt{6^2}=6$
Disorganized
@upper karma understand?
Correct
The list above is easy b.c. everything on the right is a PERFECT SQUARE: some number times itself.
But getting back to above...
72 is not a perfect square because it isn't a number times itself
But 72 = 36*2
and 36 IS a perfect square
So we do
$\sqrt{72}=\sqrt{36\cdot2}=\sqrt{36}\sqrt{2}=6\sqrt{2}$
Disorganized
and that's just fine for us.
BTW, we know we can do this from Laws of Roots (Exponents), which you might not have seen in detail yet
Don't worry about it
Splitting the root like this under multiplication is allowed.
You need to get the hypotenuse of the triangle on the front face now. Try it
AC
do you still need help on this?
if i have the relation $4\sin\left(x\right)<3\cos\left(x\right)$ is there a way that i can rewrite this as a specific inequality for $x$?
aquaticape
represent in tan?
that what I thought but somehow that messes up all the intervals where the inequality should be true
for example, 2 radians works for tan but not for the original inequality
the problem occurs when cos(x) is negative
was anyone able to solve this?
i ran a script which generated random points just to make sure there wasn't any printing mistake in the question
it seems to show that the ques is correct
use the google lens homework section it will scan the problrm and give you a solution online , it works for most questions might have a doubt in
i tried searching on google, found only 1 solution which assumed M to be on the median/altitude
To ask Unlimited Maths doubts download Doubtnut from - https://goo.gl/9WZjCW Let ABC be an equilateral triangle with side a. M is a point such that MS=d where S is the centre of Delta ABC. Prove that the area of the triangle whose side are of length MA,MB,MC is [sqrt3//12]|a^2-3d^2|
@upper merlin see if this works
i was talking about this itself, it assumes M to be on the altitude but its not mentioned in the question
oh ok
hey
If x is an angle in the third quadrant and csc(x)= -13/5, find the value for 3sin^2(x)-2cos(x) as a fraction with no decimals.
can anyone help me?
have you made any progress so far?
well i know how to solve for x kind of, but how does it being in the third quadrant affect it
you don't need the value of x itself here
huh?
the fact that x is in Q3 tells you what signs sin(x) and cos(x) are
hopefully you are able to calculate sin(x) directly from what's given to you, and then cos(x) from that and the Pythagorean identity?
When asking for help, do not insist on getting just the answer; we are here to help you learn, not cheat. Likewise, if you are providing help to others, try your best to explain and elaborate instead of simply giving away the answer.
...
Same angle, equal the terms and voila
||sounds like someone is here in bad faith||
Bro this dude be cheating in his 3rd grade homework

Who cares lol
is "rock solid logic (sarcastic)" actually an expression in english 
in russian we say железная логика which means "iron logic"
Rock solid is a thing I think
@upper karma not in a sarcastic way
Wdym? Just say it sarcastically duh


@dark sparrow what's your major if I may ask, i see you a lot here, you know your stuff
some flavor of applied math
i'm doing masters rn
i guess less applied than what i did in bachelors
...hello
do i know you?
<@&268886789983436800>
ah someone beat me to it
what even was this
it might be an alt of the person i just banned for cheating
given what they said
these people
im not even like. a Furry furry
it's the internet ma its not that deep
They are required to use cosine law
And the similarity is probably a side effect of trying to make everything whole numbers
are they actually required?
you would use it to find an angle C
or did they assume that law would be most useful here
then sub it into cosine rule again to figure out the side
Is there like a geneva convention on the brutality of problem solving methods?
assuming so is pedagogically beneficial
If you DILATE a point M(a,b) from the origin by a factor of 3, then the distance from (0,0) to (a',b') is scaling by a factor of 3
The ray from O to M is stretched out by 3. Where is this new point?
Draw it
Is it possible to express $\cos(a - b) = f(a) \times g(b)$ ?
J J
I've tried factorising it in numerous ways but i feel like its not possible? is this a provable thing?
it most definitely isn't possible.
if it were, then the solution set of cos(a-b)=0 would consist purely of horizontal and vertical straight lines on the coordinate plane
which it does not
@stuck iris
also keeping a=b implies f(a)g(a)=1 or g(a)=1/f(a) which is identically true
which means we could write cos(a-b)=f(a)/f(b) and since cosine can be zero it implies either f can be zero or infinite
both of which implies cosine should not be bounded but we know cosine is very well bounded so hence this assumption is false
though yea this is a pretty weak argument but pretty good insight regarding the problem
RIGHT i didnt think of this, thanks
Try to find the exact positions of the vertices of the triangle by using the info already given
AB=5 DE=5x2 l think (not sure)
Does it help if you prove that triangle ABC is similar to triangle A'B'C'?
Since you will find some angles in same segment if the circumcircle of A'B'C' is constructed
How would I be able to determine what single shape corresponds to the requirement if several shapes fit the description?
can someone please help me with this?
Take the given equation and square both sides
ye thanks got it.
hi
i have an exercise
given the are of circular sector= 16pi find the perimeter of this sector
just tag me please
- Since angles 4 and 7 make a straight line (180 degrees), the angles are supplementary.
- Angle 12 is 90 degrees, you can assume that the 2 other supplements are equal to 90 degrees. Hence they’re complementary. (Angles 10, 12, and 3) make a 180 degree straight line.
- Angles 4 and 5 are not adjacent to each other to make a straight line. They’re not a linear pair.
- Angles 2 and 10 are not directly opposite from each other. Also, angle 10 is less than 90 degrees and angle 2 is greater than 90 degrees.
- Angles 1 and 2 are adjacent to each other and make a straight line. They are a linear pair.
- Angles 7 and 9 are directly opposite from each other. Since angles 4 and 7 make 180 degrees and angles 9 and 8 also make 180 degrees, all 4 angles make 360 degrees. Again, angles 7 and 9 are directly opposite. Hence, they’re vertical angles
@stray pollen ^^
Thank you so much
don't give people answers
hi , can somebody help me please, how to get sine and cosine value of an angle with unit circle? for example sine 1 degrees, sine 27,7 degrees, or sine 89 degrees
Not enough information to determine
Just use the inverse trig functions 🙂
can u give some example, i can't imagine how it works
Hi how can I solve this
I know the answer by the way... just want to know why
Ignore what is there
i don't even know how to being with this one tbh
<@&286206848099549185>
What did you get for RQ?
10 cm
Great, and the hypotenuse
PR is 10 root 5
What is the area of the triangle?
Actually don't calculate it
just tell me with words, what times what
Aha, so you have PQ*QR/2 = PR*(height you are looking for)/2
and you have all other values except the height
No I am looking for the altitude of hypotenuse... height can be said as 20 if the baseline is QR
H right, so the area of the triangle is also base = PR times height H, divided by 2
Yes
Then use this PQ*QR/2 = PR*(height you are looking for)/2
Wait u can look at it from diffrence angles and get it ?
Yes, the formula is the base of a triangle, multiplied with the altitude that falls on that base, divided by 2
There are three bases, therefore 3 instances of the same formula
I think the question is more directed toward the altitude of hypotenuse theorm that I know nothing about
But... u like hacked the question
That's so cool
I don't exactly know what that theorem is, but most people would solve it as I did
And that theorem is most likely a consequence of that we went over
It probably is PQ*QR / PR is the altitude
which is immediate from ^
Are you asking if that's true? Then yes
How to solve that 2 problems
@quiet marlin
Ohh, I get how to solve that, I was just need to take arccosine of both sides, and there is ultraeasy inequality $$sin(x-\pi/6) < 5\pi/18$$
qcanser
what does it mean by (b)
start by drawing two tangent lines from the person to the tank
yes oki i just dont get how ur meant to find the cicumference visible to person
the part that's visible is the arc between the two points of tangency
hmm
consider properties of radii, tangents and right triangle trig
i get it abit but how do i find the angle
right triangle trig
i dont get that
Red portion is visible
aaaa okai thank you,, how do i find that angle from the centre
to the edge of the red portion
If you draw a line from the centre to the edge, you form a right angled triangle
Ur hypothenuse is 80
One of your side is 20
so....
mm im having trouble visualising it do u mind drawing it its okai if not T-T
ohhh wait
im supposed to find this angle using that and use that angle to find the length seen
ooooo thank you!! i got the answer
please help in this ques..
Well, A=60 degrees, B=80 degrees, C =120 degrees, D=100 degrees; A,B,C,D belong to a circle. Maybe these facts will help.
Try to think about angles which are 60 degrees. Perhaps their sine or cosine will come useful.
Also you can use the intersection of AC and BD, call it O, and find AB = AC = AO + OC.
It seems like the answer is 6/cos(80)
approx 35
Question:
If three angles of a quadrilateral are equal then it is a parallelogram. (true/false)
wdym by 3 angles of a parallel
yes but not in options
You didn't draw L and your figure is too small to read
Perhaps the problem is incorrect
any tips for proofs?
study analytic geometry
Just started studying this, the first method I learned, wondering if I did I correctly because I’m trying to understand it.
can someone help me with a few trigonometry questions?
Also the variables changed because of substitution, that’s what my book said anyways, just put into one big method to see if I understood what it was trying to say.
i understand i have to do 6400 x sin(15) but what do i do after that
@thorny forge it's 6400 cos(15°), not 6400 sin(15°). also you don't "have to" do anything. there's no such thing as "having to" do something in math.
once you have written that down, it's time to put 6400 * cos(15) into a calculator, then round to the nearest kilometer
also don't use the letter x to denote multiplication.
ohhhh sorry i meant cos aaa but the answer is less than what the calculator gives me, am i meant to take away something after it
what does the calculator give you?
calculator gives me 6223 but answer is 6182, its same with the rest of the questions asking for radius,, i dont know what i take away after

probably, it makes the last two triangles make sense