#geometry-and-trigonometry
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um wtf is even going on atm?
k @upper karma post the diagram again
nfi what that is.
no like the picture
@silent plank its angle chasing
no like the first picture
that u posted
yah
K @silent plank so OTB is 90 -x degrees
and then u do 180 - that all over 2 to get angle TOB
its actually also equilateral
there are multiple ways to do this problem
some are more efficient than others
im so dumb how did i not see that
derped, didn't realise it sooner
k so the easiest way to do this problem
is that triangle OTB is equilateral
and u know angle OTB is 90-x
so 90-x=60
and x=30....................
WAYYYY more efficient than angle chasing
umm post the diagram again
k so angle ATB is 90 degrees right
and angle ATO is x
so angle ATB-ATO=OTB
so OTB=90-x
the reason why ATB is 90 degrees is bc of teh circle theroem and point on a circle that froms a triangle with opposite points of the diamter, that point will always be 90 degrees
k
there are multiple routes to get what you need.
but you would need to justify how you determined that its equilateral
@rigid siren No.
@devout harbor are u sure
Yes
Its a rectangle so opposite sides are equal
Thus you can set up an equation where those algebraic expressions are equal and solve for a
(XY=WV)
@versed river so far I got 7. I think itโs wrong tho
a = ||10||
its a simple equation
6a-57 = 3a-27
dont click the spoiler until you solve it urself
Hey is anyone able to help me with 2 trig questions?
im just really dumb and cant get it
if you can help pls dm me
There it is, anyone able to help me understand this and help me get to the solution?
when you have sin(-t), we can move that negative sign out of the sin function
so sin(-t) = -sin(t)
iirc
what about cos, and if the first one is already negative like (b)
it applies to all of them
cos(-t) = -cos(t)
if cos(t) is a negative number, and you're asked to evaluate cos(-t), what do you think would happen to that negative number?
become positive?
correct
because let's say that cos(t) = -5
cos(-t) = -cos(t)
substitute -5 for cos(t), because we know what cos(t) is
so then you get -(-5)
which becomes positive 5
so if csc(t) = 4.5, do you know how to find csc(-t)?
-4.5?
2.5
yep
Thanks dud UwU
if you're interested in the proofs, here's a website i just found that explains them well
List of negative angle identities with proofs and learn relation of trigonometric ratios for negative angles with trigonometric functions of angles.
Thank you!
I saw this channel was free, what is the area of the shaded region?
consider the areas of the triangle AFE and rectangle ABCD
how do periodic graphs look like
periodic
they repeat over an interval

I'm confused
questions deleted
hi!
could someone help me
The angle of elevation to the top of a building is 75 degrees from a point on the ground. The angle of elevation to the top of the building from a point 20 m further from the first point is 40 degrees , how tall is the building?
@latent iron start by drawing a diagram
we know angles in a triangle add to 180ยฐ so we can work out the other angles
@latent iron
no problem
the most important part of problems like this is getting the diagram right
then normally you can see the relationships between all the values
This is not possible correct?
This is my rationale for it, they don't overlap at all and I slapped it into desmos and an integral calculator to make sure I wasn't going mad
Full desmos link^
It's not asking for the values of x where there are solutions either, just a full proof
what have you tried
try to express that 13pi/2 as the sum of two fractions
Heres a hint ||13pi=12pi+pi||
Iโve tried subtracting 2pi out of the 13pi
Why did you do that stuff on the right
Can you just go around the unit circle 4 times and end up with cot (pi/2)
Which would be 0
well, 0/1 = 0
Iโm not sure how to do it that way
Yes
So would 12pi/2 be 3 laps of the circle
Oooh, I see
Since repeating laps doesnt do anything, we can discard that
leaving us with cot (pi/2) = x/y = 0/1 = 0
What if it was something other than pi/2?
X = -sqrt(3)/2 y = 1/2
nice
so cot (5pi/6) = -(sqrt 3)/2 ALL OVER 1/2
do some more math, keep switch flip
-sqrt 3
To get the sine, cosine, etc?
Oh yeah ๐คฆ๐พโโ๏ธ
But in order to find the cot, you divide the sin/cos
Ok
Any more questions?
No thatโs it. Thank you! ๐
Soo like this?
Iโm not sure if I did this right @unique junco
well ive never seeon someone start from the left side of the unit circle
Il do a VERY ROUGH drawing
Ok
thanks
All i got is that its either 05/13 or -5/12
@unique junco that doesnโt look too rough
How did you get the 5pi/2 and the other values?
we agreed that 4pi/2 is 1 lap of the circle right?
Yes
So what would 1pi/2 + 4pi/2 =?
when you guys are done with bridge could i get some help next
5pi/2
@slate pasture This problem is simple, shouldnt take too help you out with
Not trying to be mean when I said simple, I just looked up how to do it ๐
ok. I just want to make sure I fully understand
ight send me what u found bridge
Are you familair with: SohCahToa?
me or @slate pasture
Dame
yea
So you agree that Sine = Oposite / Hypoteneus
Sorry, I'm back
You don't need unit circle for this
You can ignore ALL of the red in this
ight
Now im gonna add 1 lin to help u out
Still good?
i guess i should say, still following?
yea
So, since you know about Soh
Sine = Oposite / Hypoteneus
What is the length of the red line, which would be the "oposite" part of Soh
@knotty barn SOrry for stealing ur job, u can take over if uwant
Ok sure
Hypotenuse is 13
^
alright beacuse 13 is the radius
(-5,12) is your coordinate, so 5 is your width, and 12 is your length of the triangle
12
Yes, or you could have done sqrt of (-5^2 + 12^2) = 13
so my adjacent is -5
Nope (To helixion)
Ok hold on
@slate pasture yes Adjacent is -5
but were not looking for that because were find S = o/h
now that we know both o and h, what is the answer?
12/13
Great
so now i need to find the rotational
Helixion:
Cool bot
When your done, could you finish helping me @unique junco
@slate pasture You following along?
yea
@drifting parrot Oh sorry
Thought we were done
Yes so
you agree that 1, 5, 9, 13 are all increased by 4?
yes
@slate pasture Do you know what Related Acute Angle and Principal Angle are?
nah
Lastly, you also a gree that pi/2 gets you to (0,1) (the top of the circle)
yes
Awesome
so we do 3 laps of the circle
WHich would be 12pi/2
add 1pi/2 and get to 13pi/2
All of those points I marked (5pi/2, 9pi/2) were the number of rotations needed to get to (0,1)
I feel like im doing a terrible job at explaining this
uhh
can you join a call?
everyone gets stumped by math, dont worry bout it
Ok, I can join a call
if anyone mind checking that the last answer for number 5 is correct let me know
what do you think it equals?
what have you tried so far to find it and where are you stuck?
@slate pasture you should cover your email adress
how
use win+shift+S
to use the windows snipping tool instead of screening the whole window
or use alternative programs
lmao time to dox you now
the question is ambiguous unless it says from the starting point to the center of the circle to the wall in 90 degrees
@upper karma why do you think x=2?
this graph looks like a sinusoid overlaid on top of a line
yea it says that two functions are being added and im confused a bit
linear
well there you have it
your answers to questions 6, 7 and 9 are correct, but your answer to question 8 is not.
yea
ok i get it its 4 pi cause it starts at -1
:DDD
, rotate
@drifting parrot You can rewrite this as sin(theta) = (91) / (-10*sqrt91)
Sin(theta) is opposite/hyp, so make a right angled triangle with the given sides
, rotate
,rotate
Okay, forget the negative sign for now
Sin(Theta) = Opposite/Hyp, make a right angled triangle with the given sides
@drifting parrot Can you make it or should I?
Yes. The side opposite to the angle is of length 91
And the hypotenuse will be of length 10sqrt(91)
put em in and show me
It's because sin(theta) = opposite/hyp
why
don't you just need to figure out theta
why do you need to know the unkown side
So that we can find the other trig functions
Once we find the unknown side, we can find cos(theta), tan(theta)
and in exact form
ok. I finished solving it. I'll show you in just a minute
ah look above at the actual question
ignore me
all g
I have only seen the cropped version of the problem
Okay now you have b = sqrt(819)
You have all the 3 sides of the triangle, now you can use cos(theta) = adjacent/hyp and tan(theta) = opposite/adjacent
find their values
simplify the radical
@devout harbor
yes
Thank you.
I got it
start from the right side
and also note that cos(pi/2 - x) = sin x
@prime barn
why would you start on the right? doesn't the left look more complicated?
any chance I could see a picture of your work?
its fine
yes
watermelon poo
hmm I should've just multiplied both by sin^4 x on the second arrow would've been simplier
well thanks anyway
Damn thatโs hot
idk what it means for it to be in a form that can be graph
you should try it yourself first
cot=cos/sin
csc=1/sin
i did but im lost
when it means in a form to be graphed it means usually only one trig function
like 2 sin x
or 1/2cos x
nvm figured it out
you need to convert cot into cscx -1
using the pythagorean identity
and then factor that equation
so that its
just tell me the answer
send help my brain is blowing up
@pastel anchor have you tried drawing right triangles
huh
There are 2
how would right triangles help, i don't get it
just do it
and after if you don't know what "similar triangles" mean then search it up
i still don't get it
Do you know what similar triangles are
yea but this is about secant tangent theorem
Geometry is cool ngl ๐
yo can u give the steps m8
ACB is a right triangle
it doesn't work because it's wrong
AB is the hypotenuse
not the side
you should be subtracting
oh
what is x?
this is secant secant
its 32 right
maybe maybe not
bruh
tell me what you did
wait
product, you accidentally used addition
Yes?
can x be a decimal
ok.
Any other way to write sin(2ฮธ)?
Got it
awesome thank you :-)
lmfao whats the chances of me finding a tarzaned fan
@acoustic jungle do i make my own line on top or the bottom
if you draw the question on paper
the perpendicular bisector of that line passes through the center of the circle
and you would use pythagoras
if you think about it, the center to B would be r-4
sin A is 15/17
need help with cos(2A)
it says the identity is cos(2x) = cos^2(x) โ sin^2(x)
Yes.
cos^2 (x) is same as [cos(x)]^2
sin^2 (x) is same as [sin(x)]^2
you have cosx and sinx
Can anyone help me out with this question? "A person is looking at a boat out of a lighthouse window that is 32 m above the water at an
angle of depression of 29ยฐ. How far away is the boat from the base of lighthouse?"
diagram pls
there's none ;-;
this is the thing i was drawing but idk how to solve it if i dont know where to put the values at
plus not sure if this is even right
like this? lol
29 is on the left side
,rotate
I'm confused how they got the final answer
what's confusing u
the radical 3 over 3. how do you get that from 1/3
what do you get if you multiply sqrt3 by sqrt3
3
so maybe they multiplied the numerator and denominator of the fraction by root3?
What's confusing u
All of it is confusing me at the moment, I don't quite know where to start with part a.
Well V=<1,-5> means V= 1i - 5j
You can do the same for W now
V - W means you have to subtract their respective components( i with i, j with j, etc)
W=11i+5j
(1-11)i + (-5-5)j
Okay
So that is the answer for it?
Yes.
Can you make a diagram for part b?
yeah
Oh
It's asking for the angle
Go 1 unit to the right(x-axis direction)
and down 5
okay got it
and draw the resultant vector from the origin
how do we find the angle
well its like a triangle
tan(theta) = opposite/adjacent
1.37
78.7
do it again with degrees
okay
so the angle this vector makes with the positive x-axis is -78.7 degrees
Okay
for part c, make the diagram if you want
use the pythagorus theorem to find the length of this vector
i g2g sorry
Thank you for the help
np
c and d draw a diagram and use pythag theorem,
you dont need a diagram if you feel you dont need it
so for c I got 12 sqrt 22
im in a league game rn if noones helped you when im back i will check your answer
Anyone can help me with this? how I can solve this trig problem?
@compact spire im done
ping me when you're finished your warzone game
$12*\sqrt{22}$ is wrong
Sneaky:
@upper karma Are you still here?
Ok well do you know how to find the period
am i missing something or is that not ashby
I mean he responded immediately
Yeah maybe not
Plus Ashby wasnt online until I pinged
i pm u
but yeah, any help with that problem would be great
how do u go about solving those?
Well do you know what the period is
no, please explain
A period is when the graph completes
okok
Do you know what the formula is
usually
lets start withthat
Welp if youre busy
This trigonometry video tutorial explains how to write trigonometric equations of sine and cosine given the graph and how to solve trigonometry problems involving sine waves and temperature fluctuations. You need to determine the amplitude, period, phase shift, and vertical s...
This can help
i dont get how he says the period is 1
btw im in the middle of something rn, but im juggling this with the other thing im doing
so im sorry for the delayed responses
Ahh understandable dw about it
Well a period is the number of x axis units needed to complete one cycle
So how many x units are there before the graph repeats itself or completes a cycle
Ok can you see the point (0, -4)
how long is it on the x axis before you see another point that has the same y co-ordinate
-5 u mean?
no like
on the x axis
You see (0,-5)
When is the next time you see
(x,-5)
Like what is the x coordinate
I love geometry โค๏ธ
@versed river damn I thought I had it
so sqrt (11^2)+(5^2) isnt what im doing then
yes
it is
are you sure thats 2 root 22
or 12 root 22
whatever
should be sqrt(146)
thats irreducible
12root 22 is massive
thatd be more than 48, which is obviouslyt more than root146
@compact spire sqrt(11^2+5^2)=sqrt(146), which can only be factored into sqrt(2*73) which is obviously irreducble
would still be wrong lol
yeah
well what did you and sup? get for V-W in standard vector form?
Okay
you shouldnt need to draw a diagram if you understand how c worked
Im confused on where to start on this now
well, itd be a triangle
so you can use pythag theorem
the minus sing only changes the direction of the vector
the magnitude is still the same
can you derive a general formula for the norm of a vector xi+yj using the pythagorean theorem?
norm being magnitude, length whatever
the double lines
im not feeling too well right now. going to eat some food real quick
be right back
Okay so I need to get the double ling thing that I did with c but for v and then just do part a again?
you dont need to do anything from part a again, you already have your result from part a
So I just use my result and do the part c on it?
yes
Perfect, eating now and then I'll post my answer in a little
sure thing
Damn it really be like that
Okay Im slightly confused on this now
do you have a general idea of what the vector would look like?
so I have $\sqrt{-10i^2-10j^2}$
\sqrt
Pony Boy:
i mean its probably more appropriate to write $\sqrt{(-10)^2+(-10)^2}$
Sneaky:
$\sqrt{(100)+(100)}$
Pony Boy:
yup
Pony Boy:
yes. you can simplify that if you want
$10*\sqrt{2}$
$
Pony Boy:
yes
Any helpers on?
are you still struggling with the trig graph ashby?
repost the graph
im so confused on it bro
thanks for the help @versed river
yeah i did
but he didnt explain how he got the period, and JC explained it, but i still dont see it
Well repost the graph and we can have a look
So period is, in layman's terms, the time it takes for a period graph to repeat
can you see where the pattern starts to repeat on that graph?
starts on (-pi, -2)
it ends on 5pi
do you know what amplitude is
yea it is the max height of it
ok good
Denton do you wanna take over or do you want me to keep help them? and you find B by setting the period = to 2pi/B and solving for B
I have time, school holiday for me rn
Ahh ok, can you please take over then :)
yeah
Thank you
soso @upper karma you can also think of period, in the same vein, as the distance between two maximums or two minimums in a graph
@versed river can we PM?
sure
hey can someone help meout
just ask the question
sohcahtoa
ye
well then, unless you forgot how to divide, you now know the value of sin(ฮธ)
Is it possible that the parallel postulate is equivalent to "all triangles have 180 degrees as the sum of their angles"?
What are the units for the measure of volume?
^3 @modest vine
(length unit)^3
,rotate
be careful of signs when taking square roots
and don't mix lowercase with uppercase
simplifying $\sqrt{\sin^2(B)} = \sqrt{\frac{25}{169}}$ gets you \
$\sin(B) = \pm\frac{5}{13}$ \
and you should choose the appropriate sign based on the location of B
ramonov:
so there is sin cos and tan for things like opposite over hypotenuse and stuff but there is nothing for adajcent over opposite. Or is there one and what is it
opposite over adjacent is tangent
i know
soo the opposite of that is cotangent
oo
which is adjacent over opposite
ok that makes sense
you seem to want the reciprocal functions for sin,cos,tan which are
cosec, sec, cot respectively
have you drawn it
i dont know what to draw. what does it mean by elevation to the top of the pole is 22 degrees. and elevation to bottom is 20 degrees
yeah i dont need to draw that
no but you do
you know the height of the pole from the ground is the height of the pole + the building
Bahahhaha no I meant at the top of the building but the side
ok
youre trying though
lmao
i did it
So can you see that the height of the pole of the ground is 400 + height of pole
yes
so what angle does the building and the ground make
90
so its a right angled triangle
its a building
yup youre right
coming back to the question
the angle of elevation to the top of the pole is 22degrees
what does that mean...
Fishraider's diagram
oh
Gameson, do you understand Fishraider's diagram?
the answer to the question?
yeah
Wait do you know your trigonometric ratios
maybe
Its ok if you dont :)
is that like tan, cos, sin
any one want to help me with a test
yes
could you name them so I could be sure
yes
i jsut DID
\
sin cos tan
i got a 40
I meant like opposite
i need help sir
wdym
Like have you drawn how the question would look like
@deep trail So.... you have the height for this right
no sir
@brittle knoll sqrt(412.25)
thats the answer?
ok whats your answer
40
and give me like 3 minutes to check it
did you do tan 23 * 400 - tan 20 * 400
3 minutes
um no
i saw that the 2 degrees was 1/10th of the building so i thought the pole would be 1/10th of the buildings height
if i go live can u give me answerrs
20 degrees / 10 = 2 degrees soooo 400 / 10 = 40
it says its 400 feet from the gruond
its asking for a height of a flag
whats the formula for this
if i go live who can help me
No
soupy this channel is occupied
I said it's 40 feet high
sorry
Still wrong
fish raider can u help me
Way is it then
Gameson, can you show your steps
No, I have math jams meeting thing
soupy can you draw a diagram
Just a sec
Building is 400 feet tall. And the angle thingy from the bottom is 20. But when it is 22 you can see the top of the pole. So when the angle was 10% more u could see the top. So I just multiplied 400 by 10%
No that is not how it works
and the building is not 400 feet tall
you are 400 feel from the base
Uhhhhhh okayty
you have to use trig man
But it's not a triangle it's a BUILDING
hold on my bad
Item 2
You are holding a kite string in your hand. The angle of elevation from your hand to the kite is 44degrees and the distance to the kite is 250 feet. Your hand is 5 feet above the ground. How high is the kite? Round your answer to the nearest tenth of a foot.
Gameson was referring to his one question
Ok imagine a person flying a kite
or not flying one
5 feet is pretty short ngl
RIDING a kite
yes
where is the kite?
soupy imagine your hand is 5 feet above the ground
Hi idk how to do this. ๐ณ anybody knows? formula?
@upper karma Use exact trig ratios
im very stupid sir
it takes time
is that a cracked version of adobe products i see
I think thats the part where he is confused
OOOO CLOSE
im confused where the human goes plus where thee 44 goes
i havent done this in 3 months
would the 5 be inside?
Ok imagine
