#geometry-and-trigonometry
1 messages · Page 193 of 1
@pallid comet We simply it actually
So we just find an expression of x in terms of n
yes i fixed it to -1.1023 + pi
but it still wrong
maybe there is a mistake in the book? o_O?
Try 3 decimal places
I think
Pi - 1.102?
still wrong
Then Idk🤷
ok thank you so much guys
you both helped me very much
and there is probably a mistake in the book
it happens i hate that
How do you solve those sinosodial equations with two trig functions
give an example and i'll see if I know it
@woeful flame well, at least you know just a bit more than you did 19 hours ago lol
Can we look at the diagram?
Why AB -AD = AC - AE instead of AB - AE = AC - AD
oh, my bad
Well I don't know what axiom is that. Probably other people can help
ok
<@&286206848099549185>
,rotate 90
Use similarity
There r more specific rules I guess
Think about the side correlations
idk 😭
Can someone prove for me this statement from wikipedia?
"The size of a hyperbolic angle is twice the area of its hyperbolic sector."
@waxen gorge can you show me the steps
@pallid comet didn't someone already post
I posted something resembling that, now i have a different question
Well what's the area of a hyperbolic sector
that's a great question.
Start learning today, click https://brilliant.org/blackpenredpen/ to check out Brillant.org. First 200 people to sign up will get 20% off your annual premium...
Just watch this tbh
I have
ok leave me hanging i see
lol sorry @lament bay I'll go now
not unlike the circular case
where the area of a circular sector bounded by (0,0) - (cos t, sin t) is t/2
why not use some beautiful integrals instead of hyperbolic things
@plucky marlin that's like telling someone to integrate a circle to show (what mniip said)



well you know how the area of the unit circle is pi
it should be clear from geometric reasons that the area of a sector of 2pi/k radians is pi/k
from similar geometric reasons it's clear the area of a sector of 2pi n/k radians is pi n/k
and then with a bit of analysis it's clear the same holds for any real number
I have to compute the limit of x that approaches 0 of sin(x)/cos(x)
The answer would be 0 but can someone explain to me why that is, given they change at the same rate as x changes?
I understood it, sorry
How do you prove that the hypotenuse is shorter than the sum of the sides in a right triangle?
2ab> 0
a^2 + 2ab + b^2 > a^2 + b^2
(a + b)^2 > c^2
a + b > c
: O
@supple bramble
Yes.
I mistype it. Sry
Have you seen it before or did you come up with it on the spot?
That's a common proof.
This is like basically a corollary of the triangle inequality theorem
^
hi
in this quesion there is triangle
ABC
angle a against alfa angle b against beta and angle c against gama
i need to use the Law of Sines
but in question 1 im getting two results
44.778 that is correct by the book
but im also getting alfa=135.22
(180-44.778)
i dont understand why it isnt a result aswell?
that is the Law of Sines
@woeful flame It has to do with the order. There is a specific order for different triangles when using the law of sines. The answer of 135.22 degrees is wrong due to the fact you used the wrong order.
@empty moss what do you mean
?
look at the picture sir
there are two results also in the picture
what do you mean by the "specific order"?
i never heared about somthing like that
i know that if i got the smaller angle in the data, i could have 0\1\2 results
and when i get the bigger angle in the data I could have only 1 result
but here a is bigger then b
so angle Alfa must be bigger then 25 degree
and also 44.778 and also 135.22 looks correct
ah ok
^
yes
glad you got it
wait but there are still
two results
@empty moss no one said that Alfa must be A2 and not A1
first you gotta find the C value and the A2 value in the triangle of A2BC
Then, using that information, you can solve for the rest of the angles
there are 3 triangles,. you have to solve for all of them
theres 3 boxes due to the fact that there are 3 total triangles
ah
for the triangle of A1BC?
When solving for the length of C and the angle of gamma, did you check your answers?
the angle of gamma cannot be less than the angle of Alfa is side A is bigger than side C
you dont get me sir
for angle-Alfa = 44.778 there is one result for C
and for angle-Alfa = 135.22 there is different result for C
Ok
when alfa is 44.778, is the length of A greater than C?
i dont understand
Ok
you know Pythagorean theorem. The length of the side across from the right angle is always the biggest right?
wait what?
i dont understand this words
i probably know that but just dont understand your languege
yes
Pitagoras?
90 degree must be the biggest angle in triangle
yes
thats what you mean?
so the side across from the biggest angle must be the largest
im just getting 2 results
otherwise it isnt triangle
and dont understand why the second result is wrong
can you tell me why?
gama = 110.222
and c = 13.322
but when Alpha = 135.22
gama = 19.78
and c= 4.804
like there are 2 cases
if Alpha = 44.778
so: Gama = 110.222 and c = 13.322
if Alpha = 135.22
so: gama = 19.78 and c = 4.804
.
(2 cases)
.
why the second result is wrong?
i dont get it
that is my question
I am unable to answer this question, because I don't completely understand why it's wrong either
ok sir thanks anyway
CF and EF are parallel, likewise DE and CF for it to be a parallelogram
angle DCF = angle DEF
idk really something maybe to help
<@&286206848099549185>
@lament bay hey
I’m struggling 😔
So the basic definition of a parallelogram is a four-sided rectangular polygon with opposite sides that are parallel
Assuming our triangle is an equilateral, we can use properties of angles to prove that CDEF is a parallelogram
So we need to prove that DE and CF are parallel, as well as CD and EF are parallel
Ok
One sec
We can use angles to prove this, but do you know what the internal angle of an equilateral triangle is?
Uh not really
That's not an equilateral triangle though
Oh wait, I thought the problem said that
No worries, instead of 60 degrees we can label angles with variables instead
I'm assuming you wanna prove by similarity, then yeah
@lament bay you still there?
I know what approach we can take but I'm having a problem proving that the midpoints of AC and AB are on the same level
This is a skewed version I've drawn so we don't assume it's equilateral
Ok
ik I'm late but you can solve it with similar triangles @lament bay ?
Oh.... I completely forgot about that...
I guess we can use that intuition to prove that CDE = 180 - DCF
I mean, that literally gives you the answer straight away
And also how would you prove that without similarity?
Yea ofc
What specific theorem?
I need to just prove that since the medians are not congruent there is no way for the sides to be congruent by doing some sort of calculation or theorem that creates a falsehood
Well you can do as they said
Assume two sides are congruent and prove that medians are congruent
That's what indirect proof means
Also (tbh most commonly) known as proof by contradiction
uh huh
(-1.5,2) (-3.5, -1.5) (-2,-1.5)
Are my answers right?
<@&286206848099549185>
Need help with 14-17
Recall your trig functions, specifically SOHCAHTOA
This is prob a stupid question but is there a solution to sin(x)=i?
Sorry if this is the wrong channel
@frigid wasp
Not a stupid question, there are solutions to that yes. If you go on to take complex analysis you'll learn more about solving it
@frigid wasp you want to solve sin(x) = i?
Well we can use the complex definition of sin
Do you know what it is?
$ \sin{z} = \frac{e^{iz} - e^{-iz}}{2i} $
Pleb':
Pleb':
You can go solve that using several techniques
In the end however you get
Wolframalpha much owo
Hm it seems there are better forms
What? Example?
so i read that you can represent diection in the 3d planes
through three numbers, each denoting a rotation in each axis
like[90,50,30]
Use the direction ratios I guess ?
Thanks @waxen gorge
@devout moon you mean polar vectors?
Because only two of the numbers are angles and one is the magnitude of the vector
Help me solve the thing, for my math homework. Thanks <@&286206848099549185>
I guess Try to write some angle sum relationships and use substitution
Also, the line from right angle perpendicular to hypotenuse forms similar triangles
Any help with this? Can't see a linear algera topic: https://math.stackexchange.com/questions/3063813/adjoint-operator-g-ffff
How would I solv 3cos^2 x=7sinxcosx for 0 <= x <= 360
try dividing both sides by cos^2x
Thought so
Been off school for 2 weeks my head doesn't work u know
:p
so
3=7sinxcosx / cos^2x
then is it something to do with sinx/cosx = tan
yup
yes
mhm
use trig ratios to fill in other sides and angles
@orchid solstice use sine rule
Hi, anyone here? I got a question if you guys dont mind

On this bottom part of the example, why is it when he square roots the sin that it ends up with a + - before the answer? I havent taken a math class in almost a year and kinda forgot
oh that makes sense thanks
I got one more question if you dont mind
In this question it says that the theta is in quadrant 3, I got 1.05 after using the correct identity, the answer IS 1.05 but shouldn't it be -1.05 because it is in quadrant 3?
is that something that should just be memorized or?
it's cool for sanity checks like that, but it's not super essential to remember it
so how did you get cot ?
I plugged -1.45 into this identity
then did the algebra
I had a problem earlier that said to make sure that your answer is negative because it was in quadrant 3, so I assumed it applied to all signs
But I guess its only for sin and cos
yep
Alright cool thanks
👌
here im pretty sure you add up the number of sides to find the sum of the interior angles @marble perch
so
$$sum=180(n-2)^\circ$$ where n is the number of sides
Jaboi:
ty
@marble perch hey, did you find the answer?
yes

this makes no sense to me
shouldn't first term be y = x + 4?
no nvm
I see now
what do you need help with luv @upper karma
Well you see, for y = 10 - x
at x = 6 (R)
it is at the top of the right corner
so y = 10 - 6 = 4
So you know the height is 4
And you know that to find an area you just need height * base (length)
You know that at y = 4 is the top
so for y = 5 + x = 4 you can easily see that x = - 1
and you are already given outer length 6
how far is 6 from - 1?
Good, so O = -1
And now you know that length is 7
and height is 4
so 28 units^2 to be exact, but did you understand why?
did you follow?
i am not confident in my explainations because I explain it how I would understand
i should stop helping
For a convex polygon with equal sides, prove that the sum of all perpendiculars, drawn from a point P inside the polygon, stays constant.
I've done it for a triangle, no idea how to proceed.
square
Just keep trying more shapes, like square rhombus, pentagon etc... until something clicks?
No
Or you could do proof by brute forcing all convex polygons but that would take a while
there's an infinite amount of them?
There may be, but you are supposed to prove that the sum of all perpendiculars stay constant
Just like the sum of all angles in euclidean triangles are 180
it is constant
Looked at the answer and all you do is draw lines from P to the corners of the polygon, and sum up all the triangles. rip me I thought this would have a hard solution.
i kind of gave you that hint
since t bisects ge and o bisects gm, that makes to midline
and by midline theorem, it'll be parallel to em
you can find gto as linear pair with eto
and tog with parallel + transversal angle relationships to emo
then angle sum theorem to find g, then e
can anybody help me with a proof question on my homework?
what's the question?
sorry that’s all blurry
lmao
yes
so then, the two triangles have to be similar right?
mmhm
because if two are equal
then the third angle has to be equal
so those two triangles are similar because they are equiangular
oh
and then you can basically repeat the same process for the other triangles
it is
i don't see how this homework is supposed to be useful for geometry proofs tbh
ok
the length of the hypotenuse of a 30-60-90 triangle is 17 yards. what is the length of the other two sides?
we haven’t learned trig yet woops
wym
this special triangle
do you know that it is made from cutting an equilateral triangle?
oh yeah
well, we cut an equilateral triangle in half
the hypotenuse is from the original
the bottom side however
is cut in half
the equilateral triangle originally had all sides with 17 yards
now we cut it in half
so the bottom side should be 17/2 yards right?
so 8.5 and 8.5 square root of 3?
yeah
np
i have one more question hehe but i don’t wanna seem annoying
you really haven't done trig?
nope
ok that's fine
florida has really bad education
do you know where this special triangle comes from?
oh yeah
and then i just have to add right
div 2 equals 324
yep
IT = TG = AR = 18
oh ok
that is mostly correct
but you shouldn't have two 18's at the start
TG is 18 and that's fine
IT is not part of the perimeter though
you need IG which is 18sqrt2 instead
oh yeah i’m dumb
so just 86
yeah it said round to the nearest hundredth
then 111.56
woops 111.46
need help, 10(a) I got the answer for b, it's 9cm squared
how did you calculated 7 cm^2?
width of 7cm, height of 1cm
thanks @hard gale and @plucky marlin










anyone wanna do some trig w/ me 

ok 😃
\csc \left( \frac { 5 } { 6 } \pi \right) \cos \left( \frac { 1 } { 6 } \pi \right)
whats the latex command
tex=\csc \left( \frac { 5 } { 6 } \pi \right) \cos \left( \frac { 1 } { 6 } \pi \right)
$\csc \left( \frac { 5 } { 6 } \pi \right) \cos \left( \frac { 1 } { 6 } \pi \right)$
Yeat:
$sin(x+y)=sin(x)cos(y)+cos(x)sin(y)$
Yeat:
and thats at angle 5pi/6
yes
how do i find the roots for a radian
for example 2 pi/3
what is sin cos and the cooresponding root, and why?
@sly charm still need the answer?
hello, how would i solve for the lengths for number 17?
spam trig
Use trig functions such as tan and cos or tan and sin in order to find the missing values
otherwise known as "spam trig"
how do i know which one is adjacent
that depends on the angle ur working with
next to
I see I see
^ (You always (only like 1 case in which there isn't) have one that isn't)
Ok imma work w the 62 degrees
so then adjacent would be BC
opposite AC
yeah
hypotenuse BA
yes
Oki
hypothenus is always across the 90 angle correct?
yes
sin^-1
different things
csc is different from sin^-1
theres (should be) a button on your calculator for sin^-1
okay
got it
Explain joke plz @plucky marlin
howd u get that?
ahhh
thank you!!

use point slope form to find equations of the orthocenters
then use those equations to find the 3rd point
Not sure I should ask here but I got this function in a trig class: pi * x/(1+x^2)
The range should be R
But in the correction the prof wrote R \ { -1,1}
need help
I need to write "m" with using of a, b, c, and gama(y)
data: BD = DA
i think i should do it with cosinus sentence
but i dont know what to do
I used the Law of Cosines
and got
c^2 = b^2 + a^2 - 2ab*cos(y)
but i need to use "m" also
and I dont see how can i do that
@upper karma
do you really have the balls to take out ur phone and take a pic of your math test?
Hello, i need some help: how do i do number 19?
given are hypotenuse and opposite leg
which is a sine ratio
to find the angle using the length, use the inverse, arcsine
so i do
sin^-1 divided by 39/44 @astral hornet
np
ah yes this reminds me of A^+B^=C^
#❓how-to-get-help, rule #4: If your question has not been answered for a minimum of 15 minutes, you may use the Helpers tag once.
Please read the rules: #❓how-to-get-help!
oh my b
I'll just wait till someone hopefully sees this
very patiently
extremely patiently
<@&286206848099549185>
oof my dude you'll get me yelled at if you just @ the helpers

im gonna try it out just for fun
good luck amigo
im too daft to figure it out myself so if you solve it please enlighten me
soap:
soap:
soap:
oof its rad 45 I thought it was just plain 45
show me
sin(arccos(-2/7))
but we just got that arccos(-2/7) = theta
so plug that back in
plug in theta?
yeah
i mean replace arccos(-2/7) with theta
so it'd be sin of rad 45 / 7
=pup solve sin(arcsec(-7/2))
the bot approved the answer
woo
im bacc

csc(3pi/2) = 1/sin(3pi/2)
that's -1
so that simplifies nicely to arcsec(-1)
which is arccos(1/-1) = arccos(-1) = pi
also the range of arccos is [0 . pi]
so it cant spit out infinite values
ooo thanks
@torpid horizon dafuq
are you sure that you're in math class
and that you didnt accidentally wander into a class that teaches you how to mathematically summon satan?

im pretty sure to solve it you have to prove that angle BME is the same as angle CNE
Bae and cae
in a triangle ABC, how to prove that sum of all of the medians is greater than (AB+BC+CA)/2
You can do it with just triangle inequality
Actually what I did works for any three cevians, not just medians
Try proving that if M is a point on AB, then AB+2MC>BC+CA
What is tan?
Sin/cos
Like tan(5)
Is sin(5)/cos(5)
Ok, thankd
Thankd
Thanks
You’re welcome
name checks out
lol can someone help me w trig homework
@cobalt sun did you ever figure out that satan question? i'm only in high school geometry but i have no idea other than to use parallel lines cut by a transversal, and i'm curious how one would solve that
@upper karma which is your question?
hi guys
I tried everything I could think about
anyone have an idea how can I solve that and find x ?
i tried to make it
sin(2x)*cos(pie/2) + cos(2x)*sin(pie/2) = cosx
then get
sin2x0 + cos2x1 = cosx
then get
cos2x = cosx
I tried the answer 0 +2pie*k
what do you mean?
u know cos(x) = sin(pi/2 - x)
it's pi/2 - x
cos(x) = sin(90-x)
yeah
yeah
i just guessed
I dont think it can help
I'll try to ask again i think
hi guys
I tried everything I could think about
anyone have an idea how can I solve that and find x ?
i tried to make it-
sin(2x)cos(pie/2) + cos(2x)sin(pie/2) = cosx
then got-
sin2x0 + cos2x1 = cosx
then got-
cos2x = cosx
I tried the answer 0 +2pie*k
can anyone help me with these
looks like you can use addition method fairly easily for a at the very least
@wild pasture set up as matrices and gauss eliminate
Can someone help me with geometry in DMs?
It’s kinda advanced
@flat cobalt still need help?
Looking for some help with this
lemon catto:
How is it different than this : =
its pretty much the same thing
sorry to disturb but can someone explain why sin(x)>1 means that there are no solutions
basically the question is asking me to show that, 2sin^2(x) +5cos^2(x) =1 has no real solutions using 3sin^(x)=4
3sin^2(x)*
😩
A rhombus has sides 10 cm long and an angle of 30°. Find the distance between a pair of opposite sides.
Anyone know how to do this
draw out the shape and label it with known dimensions
solve for other dimensions using rhombus properties
then draw in line for height, and use dimensions to find length
Double angle identity?
60 + 60 = 120 maybe
2 tan 60 = tan 120 * 1 - (tan(60)^2)
Can someone help me with the easiest geometry?
a^2 + b^2 = c^2
Triangle ABC is an isosceles triangle. AB = AC. What is the measurement of ACD?
I’m trying to see whether my answer is correct or not
lol you should just read the definitions in your book
Haha lmao
I’m stupid, and I can’t figure this out
Would you mind helping with this thing?
You just need to read the definition in your book about exterior angle in a triangle
Can you spell it out for me
I don’t have a book 😭
We’re not using textbooks
My teacher explains it all
I accidently spaced out when he was explaining this
What the hell, how does he teach then? Are you in america?
Anyway this is the theorem
Theorem: An exterior angle of a triangle is equal to the sum of the opposite interior angles.
Is that correct?
What is it asking exactly by saying Measurement of ACD
That is the interior angle
the angle
The exterior angle is ACD*
I have no idea
ACD can only be an angle, theres no way to deduce the length
@fiery badge he means the angle
Anyway now you konw which is the interior and exterior angle right?
No, exterior angle is ACD which you are trying to figure out
ACB is the interior angle wich is already 55
"I think the answer is 125 degrees"
@fiery badge shut up
lol rip
Ok dude
Well, the opposite sides do add up to 125
And the bottom right corner of the triangle is supplementary to the exterior angle, I am guessing?
So, 180 - 55 = 125
B is the exterior
The theorem is just that these two angles should add up to 180 degrees
Which is 125 so, I guess I am right
Yeah
Why was I told to shut up?
No idea
He clearly understood that from the beginning
you just over complicated it for no reason
He didn't
Why would he ask to verify the answer if he understood it?
If he understood it he would be confident that the answer is 125
Not ask if it's right
Hes asking because he wasnt sure what the actual question was asking
smh
as he said earlier
It’s fine guys, lol. Don’t fight xd
People ask questions simply for verification, I do so sometimes
I got another problem though, which I am literally having a hard time. My teacher said this problem is easy but hard at the same time
Let me pull it up one sec
What's the point of that, that just means you don't understand it
Or perhaps there is no mark scheme available
Better to ask for an explaintation instead
You don't need a mark scheme if to verify your answer if you understand it lmao
that has to be the dumbest thing Ive heard
what if you fully understand your method, but your method is false?
if someone says no you are wrong then you can ask why and find out where you went wrong
it's not that complicated for his question, Im sure he gets it
Here
I wouldnt have responded like this if you didnt just tell me to shut up for no reason
How do you even solve for x? I got no idea
You can deduce some of the angles
What does that even mean? 🤔
@fiery badge what
the triangle with the 60 and 50 degree angles
you can find out the other interior angle within that triangle from that information
What does deducing angles even suppose to mean lmao
understanding your method is not the same as understanding your answer, I clearly said that if you understand your answer you should have no problem verifying it, understanding the question or method doesn't necessarily mean you understand the answer
what
"if you understand your answer you should have no problem verifying it" and what if the logic youre using to verify it are false?
Has anyone solved the problem, yet? 🤔
?
@fiery badge then you're not following the method right and thus not understand it ?
the methods usually have clearly defined steps and definitions, so it's impossible to misverify the answer if you understood the method
but if you told him his answer was right maybe he could try explain it and you could verify his method
saves a lot of time and confusion
if you misverify it then you clearly didn't understand the method thus why it should be explained instead of just verifying and spoonfeeding the other party

yeah true, but most people here just go with a "ok thanks" then move on and ask similar question
if you wanna be wolfram go ahead
No but theres only one way he got to 125
there isnt much depth to this question
if he got 125
he clearly knows how he got there, by applying whatever laws/ rules he had
exactly, so why should he need verification ???
i would side with you perfectly if the question was a little more complex
just so he knows with absolute certainty that he is correct?

You're telling me you've never had a class and then asked your mate "What did you get?" just for verification?
then just tell him that theorems are well defined so he don't need nothing else to be absolutely certain
yeah, but only when i didn't understand it, i never ask if I understood it

I just answer questions because they are fun, if the op inquires into my method I proceed accordingly. I may ask them if they understand, just to make sure.

@graceful trail i dont use white discord, can't help you sry
What does that mean? 🤔

cant see it
Ah
screen too dark
Okay, hold on
i suggest you label that point in the middle
and the point in the far right to make it easier to explain
It’s not necessarily have to be solved, my teacher just wanted to try it out
E = ?
Verifying, lol
I thought I made a right triangle
So, I was thinking it could be 30
k, no more verifying be absolute certain from now on
Alright
now make a triangle out of BFC
You do? Enlighten me
Hmm, I’ll try my best lol
Actually nvm, lol
I thought it was 110 for a second
But nvm
You made a mistake, F is actually 50, the C in BFC is just 50 not 50 + 30 (exterior angle)
O
I see
Ok, now what?
I tried using algebra to solve x, but turns out, I was wrong, I think
Why algebra? You can jst find out all the angles
Have you figured the answer though?
I can't figure this out oof
xd






