#geometry-and-trigonometry
1 messages · Page 108 of 1
by memorising it 💀
memorize only a few basic ones, and learn how to DERIVE the others from them
okay im being real, if you practive enough (diffrent for diff ppl) then you will automatically see the pattern, you will build muscle memory, hence youll not need to memorise it
I know a few but sometimes I get stumped
so, PRACTICE is the key
in which std are you?
?
class/standard
calculus
I don't understand trigonometry
I have a hard time with $sin\theta := \frac{\text{opposite}}{\text{hypotenuse}}$
Andy
what do you mean
With the quotient rule...
I am having trouble understanding ratios and things that come from geometry
what concepts of trig do you need to know
this is not usually called the "quotient rule"
anyway maybe review the very very basics then. working with identities will take more firepower!
Yes. I don't really understand trigonometry
I want to
if you're going to self-study, have you tried Khan Academy?
No
hey! im doing khan academy rn
aight then go learn yourself some trig on khanacademy
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https://physicswallah.onelink.me/ZAZB/4mlvx216
Master CBSE Class 10th Maths Trigonometry in just one shot! This video provides a complete and detailed explanation of Trigonometry concepts in pure English, perfect for quick revision and deep u...
sophia
hola hola coca cola
a=20301125
circle theorems are soooo hard
Easiest
There is more to it in higher grades
exceptionally when we use them in complex plane and coordinate geo
it becomes manageable
Frr
Guys help
draw the diagram first
correct answer is (2) 110
help pls
What step are you on?
1. I don't know where to begin.
2. I have begun but got stuck midway.
3. I got an answer but I was told that it's wrong.
4. I got an answer and would like my work checked.
5. I have a question about someone else's work/solution.
6. I have completed the problem and don't need help anymore. Thank you.
7. None of the above
2
i feel like the triangle could be important...
well im just angle chasing rn
if you had the angle Z or Y you could def do the problem easily
but idk any other way
Draw a circle
Specifically note that ||if you define the top right and bottom right vertices of the rectangle to be B, C (respectively), then B, C, X, Y, Z are all concyclic||
what the sigma
can someone please tutor me?
10
can u help then?
tysm
bro 10th grade, rly!?
ok , but lets be honest, gravity isnt a force, Sir Newton
ik it isnt
general relativity says so
yep
u a nerd too?
like i am intrested in nature of matter
what is 'nerd' for you?
quantum feild
like studying and reserching
QFT?
ok then i might be inclined towards that
nah, intresting, i have learned about feynman's path integral and bohr atomic model , that would embarked the intrest even more
damn, how it went?
hmm
good
i have to keep my name
slept at 12 woke at 3
studied
u r in which standard?
broo
yeah?
ok, (if that is personal)
is a range good?
wdym
not age but grade,std,class
yeah ig
you could say like im in high schoool, university etc
,uni?
k
do you have more intrest in mathematics or in physics?
they are highly interdependent but then also
got it, cya
accept Friend req
Can I dm ? For physics help 😅
np
He hath been summoned
i thought i could understand what this means
you have to find the length of the red line
given these are squares and theres a right angle triange
What step are you on?
1. I don't know where to begin.
2. I have begun but got stuck midway.
3. I got an answer but I was told that it's wrong.
4. I got an answer and would like my work checked.
5. I have a question about someone else's work/solution.
6. I have completed the problem and don't need help anymore. Thank you.
7. None of the above
Hopefully you remember that the altitude of a right triangle splits it into two smaller triangles that are each similar to the one you start with.
Determine yhe height of the right angles triangle using similarity of triangles and since the part of the red line is perpendicular on on noth sodes of the square ,u can js say that it is equal to its length i.e. 5
the part of the line crossing the square is not parallel to the length of the square
wait hold up
i think he drew it crooked
but that doesn't mean the line ends at the center of the square
Ignore the solutions in pink
I got that 4x+5y=90 due to it being shown
But idk about k and c
180 - (4x + 8y) = a and 90 - a = k
c you should be able to deduce from 4x + 8y as well
so you should actually find c first to make it easier for yourself
Bro I'm lost
How do you solve for x
(4x + 8y) and c are what types of angles?
Oh I see it now
I'm prompting you right now
What about solving for x and y
yes, so you get y = something * x if you do that
but now you also have the equation 4x + 5y = 90
so that leads to a linear equation in x
Yes
But I need a second one
to eliminate the x or y
you already know that c = 7x + y/2
Yes
you try it yourself first
3x-7 1/2y ?
where did you get 3x - 7?
7x+y/2=4x+8y
ah, there's no equal sign here, so I got confused
you meant 3x = (7 + 1/2)y
yes, that's correct
Yes
If you added them to the same side
Wouldn't it be equal to 0
yes
or you meant 3x - (7 + 1/2)y = 0, yes that's also correct
sure
did you get x = (5/2) y?
No
I got x=15
so 4x+8y = 108
the top angle of the triangle is 90
so 90+108+a=180
how did you get 108?
wouldn't that make a a negative?
108 = c
yes but that's the teacher's solution right
from the diagram you can't know that
I just got it
ok fair enough
4x + 8y = 108 and 4x + 5y = 90
Yes
then you can figure out y
What I want to figure out though is how I can get it from the triangle without sub
yeah x = 15, y = 6
oh jeez
it's so much easier if you sub though
oh, so you want to know what the problem with this step is
one sec
I got k=-18
well by angles on a straight line, a + 108 = 180
Isn't a triangle 180 though
Oh I see it now
Ok thank you
I need to wake up in 6 hours
Thank you for the help
no worries!
In my idea of partial dimensions we take finite cartisan plane 1 D and make it so only 28% of 1D can extend into 2D
For fractal dimension 1.28
There are many to ways to do this but if you distribute it randomly you and draw any shape
The shape will become fractal
Just like how line like fractals are generated in computer
Lets say 28% of space can access 2D in interval [x1,X2] on a line
28% of region can access 2D for all distance function D(x1,X2)>4
why trig isn't anymore in here 
I mean they are talking about angles I just wanted people's opinion on my idea since other channels are busy I posted it here also since I am yet to go to college it fits
\begin{gather*}
\text{Inverse trigonometric identity chart.} \
\text{Have fun!} \
\
\color{red} \sin(\arcsin(x))=x \
\color{red} \cos(\arcsin(x))=\sqrt{1-x^{2}} \
\color{red} \tan(\arcsin(x))=\frac{x}{\sqrt{1-x^{2}}} \
\color{red} \csc(\arcsin(x))=\frac{1}{x} \
\color{red} \sec(\arcsin(x))=\frac{1}{\sqrt{1-x^{2}}} \
\color{red} \cot(\arcsin(x))=\frac{\sqrt{1-x^{2}}}{x} \
\
\color{orange} \sin(\arccos(x))=\sqrt{1-x^{2}} \
\color{orange} \cos(\arccos(x))=x \
\color{orange} \tan(\arccos(x))=\frac{\sqrt{1-x^{2}}}{x} \
\color{orange} \csc(\arccos(x))=\frac{1}{\sqrt{1-x^{2}}} \
\color{orange} \sec(\arccos(x))=\frac{1}{x} \
\color{orange} \cot(\arccos(x))=\frac{x}{\sqrt{1-x^{2}}} \
\
\color{yellow} \sin(\arctan(x))=\frac{x}{\sqrt{1+x^{2}}} \
\color{yellow} \cos(\arctan(x))=\frac{1}{\sqrt{1+x^{2}}} \
\color{yellow} \tan(\arctan(x))=x \
\color{yellow} \csc(\arctan(x))=\frac{\sqrt{1+x^{2}}}{x} \
\color{yellow} \sec(\arctan(x))=\sqrt{1+x^{2}} \
\color{yellow} \cot(\arctan(x))=\frac{1}{x} \
\
\color{green} \sin(\arccsc(x))=\frac{1}{x} \
\color{green} \cos(\arccsc(x))=\frac{\sqrt{x^{2}-1}}{x} \
\color{green} \tan(\arccsc(x))=\frac{1}{\sqrt{x^{2}-1}} \
\color{green} \csc(\arccsc(x))=x \
\color{green} \sec(\arccsc(x))=\frac{x}{\sqrt{x^{2}-1}} \
\color{green} \cot(\arccsc(x))=\sqrt{x^{2}-1} \
\
\color{blue}\sin(\arcsec(x))=\frac{\sqrt{x^{2}-1}}{x} \
\color{blue}\cos(\arcsec(x))=\frac{1}{x} \
\color{blue}\tan(\arcsec(x))=\sqrt{x^{2}-1} \
\color{blue}\csc(\arcsec(x))=\frac{x}{\sqrt{x^{2}-1}} \
\color{blue}\sec(\arcsec(x))=x \
\color{blue}\cot(\arcsec(x))=\frac{1}{\sqrt{x^{2}-1}} \
\
\color{magenta}\sin(\arccot(x))=\frac{1}{\sqrt{1+x^{2}}} \
\color{magenta}\cos(\arccot(x))=\frac{x}{\sqrt{1+x^{2}}} \
\color{magenta}\tan(\arccot(x))=\frac{1}{x} \
\color{magenta}\csc(\arccot(x))=\sqrt{1+x^{2}} \
\color{magenta}\sec(\arccot(x))=\frac{\sqrt{1+x^{2}}}{x} \
\color{magenta}\cot(\arccot(x))=x \
\end{gather*}
₊‧°𐐪♡𐑂°‧₊ Usagi ⋆౨ৎ˚⟡˖ ࣪
thats not right because the drawing is not accurate, the red line is not the same length as the part of the hypotenuse u picked
All you need is to make a triangle 
Yes, my mistake, the answer is 35/3
Hey can anyone tell me how to solve this?
It's not a big deal if you understand them...
in fact, there are many, many more than that
just calculate it.
How to Compute sin(5pi/3) by Hand
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this video does a good job of explaining it
@split lance it's definitely Pythagoras from my previous experience, probably something like this
wait I'm blind
the radius is 2, totally forgot
so that means triangles ORQ, OQP are equilateral
yes, then if you can find the 'height' of trapezoid TSRP, you're good (there's a nice way again with Pythagoras)
$\sin(\frac{5\pi}{3}) = \sin(\pi + \frac{2\pi}{3})$
equals, not implies
and is it better if i rewrite it as $2\pi-\frac{\pi}{3}$?
Kaladin.
Kaladin.
okay
here is my way of doing it,
sin(5 pi /3)
sin(300 deg)
sin(90 x 3 + 30)
since quotient is odd, we convert the parent func into its co func and since the ray lies in 4th quad, add -ve sign.
so
-cos30
= -root 3/2
btw how did you used teXit? what was the command
There's no command to use -- it acts automatically on any post that looks like it has TeX formulas in it.
I believe it triggers on the presence of either dollar signs or \( or \[ (and their right-end counterparts).
You didn't enclose your formula in dollar signs.
$sin(x)$
Aeronix
wait, it works!!!
tysm!
how to type pi?
$pi$
There are links to many tutorials in the pinned message in #latex-help; otherwise use #latex-testing for experimentation.
My way of doing it would be the classic standard unit circle method . Can be written as 2π - π/3 i. e. 4th quadrant where sinx is negative. So it would make it -(sin{π/3})= - √3/2.
I need a playlist for trigonometry which is like not too long
ok
Hello
is anyone here good at geometry tutoring?
I need to pass my Geometry EOC retake because I got 395 on the first one
twin we rocking on the same boat im taking geometry and statistics honors 
tryna make a 4D game was a horrible idea
4D cubes are managable, but beyond that?
gulp
i would imagine you need a good grasp of 3D geometry and/or 3D modeling software before advancing to 4D.
its a grid based system
mostly just works by shuffling arrays in order to display 3 of 4 axses at once
Problem VI:
Given acute angled triangle ABC (AB < AC).
Let K be a point on line AD (K != A, K != D), and M be a point on line DC (M != D, M != C).
Ray BK intersects AC at point E, and ray CK intersects AB at point F.
Perpendicular bisector of EF intersects AM, MK, AD at G,I,H(respectively).
Perpendicular bisector of HD intersects EF at point T.
Prove that (AEF), (AIG) and (THD) meets at a common point.
My idea is that we are going to prove ANFE and ANIG are cyclic quadrilaterals, then the proof is complete
I'll now let N be the intersection of TA and (THD)
so we are going to proof TN.TA = TI.TG = TF.TE
but Im kinda stuck here. We can also let S be the intersection of EF and BC, and we have angle HDS = 90 and TH=TD then TH=TS
but still stuck. anyone has an idea? thanks
Dang
Hopefully we pass the EOC
I almost passed by 9 points 😭
Hi I got stuck on this :
cos^2(x/2)+sin(3x)=1/2
=> cos(x)+2sin(3x)=0 and I don't see how can i simplify more...
this is a nasty problem
probably cos^2 x = 36 sin^2 x - 94 sin^4 x + 64 sin^6 x and then it's a cubic
oh wait let me fix the equation
you need to use the triple angle identity to expand sin(3x)
then square both sides
I saw this and then I said to myself sin^6 there is no way
thanks I will try with that
no, sub in sin^2 x = t
actually, easier is $6-\frac{8}{1+\cot^{2}x}=-\cot x$
south
yeah then it's a quadratic, there you go
We can't even imagine 4D so how is it possible to jump on 4D or create 4D games
also, screens are 2-dimensional
so they use perspective drawing and other visual tricks to make 3D objects look read on a 2D screen
True
yeah so you'd need to have separate 3D views and that would be as far as you could go
individual 3D cross-sections of the 4D space, projected onto 2D
i mean, look up 4D golf
its creator made devlogs about it
Is their a 4D game also
i don't understand your question.
4D Golf is a video game, and yes it is 4D. the genuine kind.
by that logic, we would need a holographic screen to display a 4D obj, isnt it?
<@&268886789983436800> spammed across many channels ^
I do Not want to write two column proofs mr teacher guy
Yeah ong
I think a reflection by definition means that if A goes to B then B goes to C
guys help
im trying to figure out the anme of two angles
when two parrel lines intersect one
anme?
name
are they vertical angles or
tranversal angles?
tranversal lines is what im talking about
whats the name, im on the geometry aops book rn
this?
oh, so vertically opposite angles
yes
this is in chapter 3 of the aops geometry book btw
thx
Who is studying this ??
@silverrolt
Class 7th students😂

probably
Hi
||Lấy J là hình chiếu của K trên AT. Lấy giao điểm của BC và EF là L.
Các hàng điểm điều hoà cần biết đối với bài này: (CBDL) = (EFHL) = (GIHL) = (AKHD) = -1
Dễ thấy TJKN nội tiếp -> AJ.AT = AN.AK = AH.AD (hệ thức Maclaurin)
-> TJHD nội tiếp.
Biến đổi góc rồi chứng minh ∆TJH ~ ∆THA
-> TJ.TA = TH^2 = TF.TE = TI.TG (hệ thức Newton)
Từ đó suy ra được 3 đường tròn ngoại tiếp đã cho ở đề bài đều phải đi qua điểm J||
@slender sparrow ping me if you have any other questions
Lol
Trillions of points
oh my what is this gibberish
Which concept this this. 💀💀💀💀💀💀
I had a headache plus it’s not in English fuck I’m dumb AF lol
From what I’m looking at it might be harmonic bundles and power of a point but idk
exactly
Is this correct?
False
False
True
False
True
IM BACK. can someone help me with how to prove that the 2 opposite side angles of a isosceles triangles are equla
Reposted here: #1422429158188908595 message
Yep
Start by drawing a median to a side
This will divide the triangle into 2 triangles
These triangles have common sides and 90° angles , they will be identical by hypotenuse side test.
So , by this, corresponding angles will be equal too
Should I create a separate user account on my PC for gaming, and why would that be helpful?
Is it necessary to use a game controller for PC games, or is a keyboard and mouse enough to start?
Wrong server.
Nope, use your school account.
Wrong question dude
Someone needs a ban
cảm ơn nhé
Can anyone proof why sin 0 is 0
U can do that using a right angle triangle or a standard unit circle
how do i prove that l1 l2 l3 are concurrent with an equation connecting a b and c?
take any point on unit circle, now it makes an angle x from the initial ray, hence its coordinates are cosx,sinx
meaning the height of the point from the initial ray is sinx, now watch what happens when x approaches to 0, then the height of that point decreases, hence sinx also decreases(i.e it approaches to 0) so when x = 0, sinx = sin 0 = 0
Exactly, it's the most basic thing taught in trigonometry
Since all three lines pass through the same point (say O), the angles around point must sum to π on one side of a straight line.
If you start with three arbitrary lines, their pairwise angles won’t necessarily satisfy this relation.
But if they are concurrent, then necessarily:
$a+b+c=π or 180°$
Sherdil
Compile Error! Click the
reaction for more information.
(You may edit your message to recompile.)
Using vertically opposite angles, a+b+c = 180, which is condition for concurrence of lines passing through a point
Reposted here: #precalculus message
stupid question but what is this called in English
hard time fidning anything because my translations are off
unit circle?'
It's a trick to remember signs of trigo functions in all 4 quadrants
Eg. Sign is positive in 1st and 2nd quadrant
The trick is as "Add Sugar To Coffee"
A = all positive in 1st qd
S = sin (& cosec)positive in 2nd quadrant
T = tan(& cot) positive in 3rd quadrant
C = cos (& sec) positive in 4th quadrant
All sin tan cos rule
i see, mine's was a short trick to remember it
I haven't heard this mnemonic in my trigonometry class before that's neat
is there any way to complete the square in desmos?
i know how to do it manuallyfor SAT but just curious if possible with regression or something
Graph it and find the vertex, and then use another equation to solve for slope?
you don't have to idt
js use the equation of the circle as (x-x_0)^2 + (y-y_0)^2 = r^2
and then expand that
oh mb
didn't see the manually part
You can find bcd = 180- edc and then find cbd and finally cad
Do not know where to start
why is bcd 180-edc
Oops my bad i meant bdc
Triangle cbd => sum of 3 angles=180
Sat is so easy dudee,
@royal grail hello there.
I haven't seen your work, but I'll give you some clues.
Try adding the common angles like angle ABD and ABC share a common vertex and line.
In simple terms, if angle ABC is divided into two parts, 60 and 20, adding them both would give you back the whole.
It would be 80.
It would apply to most given, including angle BAC.
Would be 80.
If you recall, the sum of the three interior angles in any Euclidean triangle is always 180 degrees.
Yo supe
I guess this guy just wanted someone to solve it
Didn't need help
(pure angle chasing doesn't suffice without some kind of construction)
.
i believe it is x = 60degress
Obf=90, dbf=102=>obd=12
Ob=od=>isosceles triangle=>obd=odb=12
ok so i dont recall asking
like what could possibly be the point of responding to this if you have nothing to add
the massacre
ODB = OBD = 102° - 90° = 12°
Okay this isn't for any help, but does anyone else just forget basic math during a test?
bro i have no words to express the feeling
I mean depends on what you mean by basic
never, that's js in veins now'
build up to polygon and its done
hello?
langleys adventious angles problem
Hello, Could someone explain Thales' theorem? I'm studying and looking for other ways to explain the theorem
Those are certainly writings
hi, is geometry or triganometry the subject that teaches about angles
Yes
great :D
I had a question that said “if the width of a rectangle is 5 more than the length and the perimeter is 106 what are the dimensions of the rectangle?”
I completely forgot how to do it lol but then I figured it out later in the day
This
perchance were the length 8.33 and width 44.16
Through:(4,0)and(2,1)
The perimeter of the shaded area is 2π + 8 and the lines PQ and PR are tangent on Q and R, respectively.
Because the lines sre tangent on the circle, then the radius is perpendicular to the lines. Call the point of the center of the circle C.
If RC is perpendicular to PC and RQ perpendicular to PQ, then we have that PRCQ is a square, and PQ = Radius of the circle. Call PQ = x
Help im stuck here
Its geometry for me
It's to find the radius
If the arc length is xπ/2
Then I have that
2x + xπ/2 = 2π + 8
4x + xπ = 4π + 16
x = (4π+16)/(4+π)
Is this the answer
There's a little more simplifying you can do, but yeah
How
4pi+16=4(pi+4)
Sorry I took forever to answer but the length was 24 and the width was 29
So it becomes 4(4pi)?
4(pi+4)/(pi+4)=4
area
can any1 explain to me why the image of orthoconter of a triangle about any of it's sides lies on the circumcircle of the triangle
Is it a 3d figure
??
I guess it is
Divide the area into 3 parts
nuuuuu im wrong 😭 what formula did you come up with
also no worries :D
Can anyone help me revise on triangles and circles?
You still haven’t post the work you’d like to be assisted with.
like helping me see the connections in general
i just get lost once I see the shape
Do you have a sample question?
It’d take a lot of time for us to guide you from the very beginning
Like a book that's just questions
like in general, i jus tcan't see which ones connect w each other
Still, too open as a question. It's almost impossible to do this via Discord
That's why we're asking you if you are finding difficulty with some specific exercise
Of course, precise theory questions are much appreciated too
For example, we have a triangle ABC, a circle (O) with diameter BC intersecting AB, AC at D, E. Call the point that which BE and CD intersect H and the point where AH and BC intersect F. Through D draw a line that is perpendicular with BC that intersects (O) at D1. Prove that E, F, D1 are collinear.
like there is info, i just can't connect them
I tried that but it didn't work
Show me what u did
It would be easier if it went through the center
I divided it into these three areas
I think it needs to be divided into 4 parts... Other part would be the blue part extended inside... But it would be of different lengths so u need to use some geometry or integrate using limit.
We’re given the perimeter, which is 106 and we know that width is 5 more than the length. So we can setup an equation based off the formula to find the perimeter of a rectangle which is P = 2L + 2W, so we can plug our numbers in, 106 = 2L + 2(5+L). Solving for L gives L = 24 and we know that the width is 5 more than the length so then just do L + 5 which gives 29 for our width.
ahhhhh awesome! I see what my issue was, i added all sides and forgot that rectangles have their own perimeter calculation
:D thanks!
my second mistake was multiplying by 5 and not adding 5

if the radius of the spheres is r, then the height is 4r, the length and width are both 2r, because the spheres exactly fit
from there, you should be able to find expressions for the area of the cuboid and the spheres
Find the volume of the box then find the total volume of the two spheres and subtract it from the volume of box... Divide it by volume of box and multiply by 100
So basically u use percentage formula
Final-initial/initial X 100
Red trapezium:
tan(27°) = 0.0625/x
x = ...
Base = b = 0.25 + 2x
Area = A2 = ½(0.25 + b)(0.0625) = ...
Thin orange isosceles triangle:
2 same sides = radius = 0.241
Base = b = 0.25 + 2x
Height = h
h² + (b/2)² = 0.241²
h = ...
Area = A4 = ½bh = ...
(or use Heron's Formula directly)
Light blue reflex circle sector:
Peak angle of thin orange isosceles triangle = a
½(0.241²)sin(a) = A4
a = ...
(or use Cosine Rule)
Reflex angle of circle sector = t = 360° - a
Area = A3 = (t/360°)(pi)(0.241²) = ...
Green part:
AD = 0.25/2 = 0.125
tan(27°) = DE/AD = DE/0.125
DE = p = 0.125 tan(27°)
EA = q = sqrt(p² + 0.125²) = ...
Triangle ABC:
AB = m
BC = n
ABC ~ CFE
AB/BC = CF/FE
m/n = (0.125+m)/(p+n) = tan(27°)
m = ...
n = ...
AC = sqrt(m² + n²) = ...
Radius = R = EC = EA + AC = q + AC
Area = A1 = (78°/360°)(pi)(R²) - ½q²sin(78°) = ...
Total area = A1 + A2 + A3 + A4 = ...
Small triangle:
70° + 30° + y = 180°
100° + y = 180°
y = 180° - 100° = 80°
thxs
np
use angle sum property to find the unknown angle in the triangle then use corresponding angles property to find y
<@&268886789983436800>
,rccw
so we know that the volume of the box is LWH
@gloomy spear
Since the spheres are identical
And they touch the top and bottom
the diameter is x/2
so we have
,,LWH = \left(\frac x2\right)(W)(x)
calvin
so thats the volume of the box
For the spheres
since the diameter is x/2 the radius is x/4, half of the diameter
calvin
so we have
Since there are 2 spheres in the box
We multiply this by 2
Giving us
,,V = \frac {\pi x^3}{24}
calvin
calvin
Oh my god sorry for the super late response but, you are very welcome!
Gotta love math
I know this
:D thank you! and right? im learning to love it!
I used to dread any kind of math from elementary to the beginning of high school, but when I got into my sophomore year, we were learning basic trig, just how to find the angles or sides of a right triangle. All of a sudden, everything clicked. I went from not understanding any math to it being my favorite thing to learn. Now I'm in Honors Precalculus; sadly, my school doesn't offer any higher math classes.
awww thats sad u gonna do dual?
im doing ap precalc right now c: so i guess we're about the same
I was gonna do dual for math, but I decided I would take a comp sci and mandarin class for dual enrollment
The only complaint I have for my precalc class is that we get into actual precalc next semester, so the first half year of my school year is gonna be review
What is trigonometry even about? Why do we need it for linear algebra en calc1
lol
ours is ap so igs we js follow the general curicullum yb college board
its so ez rn i have a 99%....
LOL yeah my precalc H is actually so ez its not even funny
I wish my school offered more AP classes we literally have THREE APS
THAT IS IT
is there a general chat in this server?
try #discussion
we have like
4 math aps alone
precalc ab bc stats
i feel bad for you...
hm I have no access to that cahnnel for some reason
i have "i like math and i'd like to chat about it" selected that might be it
I have the same things
hmmm
you have the studying! role due to selecting "hide the discussion channels" in id:customize
ohhh
it says I have it off?
you do now
yayy
As I was saying before, the only APs we have are AP Lit, APAAS, and AP Gov
damn
I go to a ghetto school, so I'm not surprised tbh
I knew I should've gone to that tech school 
thats so cool! its absolutley awesome when once the idea clicks you start wanting to do it with earnest
and congrats aswell :D
Yall i did this trigonometry question like this, i asked chapt gpt if this was another correct way of doing the question but i could not like exactly comprehend my answer so like idk if this way of doing this question is correct or not, can any1 tell? (I did it in another way than shown on google etc)
!nogpt
Please do not trust ChatGPT or similar AI tools for mathematical tasks, as they often generate output which "sounds correct" but has numerous factual or logical errors. Use of these AI tools to answer other people's help questions is strictly against server rules (see #rules).

Did any of you studied
Sin(a+b) and cos(a+b) in class 10 ?? 😭
I do
Seriously 😳
either grade 10 or 11
idk i did this
in 9th grade
sin(a+b) remember it like sinacosb + sinbcosa, so put sin and cos in the first and you give them the respective angles
for the next one
switch them up
thats how i remember it
This one is easy
But cos ones
cos(a+b) = cosacosb - sinasinb lmao
thats the easiest
just cos with both angles
and sin with both angles
Maybe when I will study in unit circle then is might be easy to understand
just remember cos in the first and sin in the second
and for each u give two angle to both of them
ngl i still remember it this way lmao

it just never went away
Habit 😅
but i don't have ot remember them anyways i got a sheet full of trig functions
im gonna neet
just keep on using them made them remember lmao
thats the trick
don't even learn it just keep using them you will learn them
Bro but one thing I find hard is identify proving question
Like how would I know we have to divide by cos²A 😭
Can I share pictures in this channel ?
🙏🏻 those problems were the end of me in the beginning of school bruh thats a fair issue but onlu thing which got me good was watching one of these youtube videos and solving along eventually i was able to do them MOST of the times
that most of the times was enough to get me good grades
actually A+
lmao
i just solved them like crazy i eventually got the idea
also cuz some of the less attention student was able to somehow do it better then i was and that shit made me crazy i was like HOW CAN HE DO IT HOW HE GET THE IDEAS
i was locked in
See this question there are two problems
- logic
- mixture of 2 chapters
do u mean quadratic as a second
chapter
Very basic question
Yeah I mean it's basic but still
How's that basic if you are doing it for first time 🥺
It took me 5 mins to realise I have to divide by cos²
Can anyone help me figure out if my way of doing this question is correct or not 😭
It is in 10th, im in 10 rn so..
Which board?
Cbse
Like the question i clicked a pic before of, i js wanted to know if the way in which i did the question was valid or not of trigono
Wait let me also solve and send to you 🫡
I think it's correct but you can do like
Taking value of tan as P & B
Then finding H and using the ratios find the solution
Yes i saw that way on google but I thought this way was easier for me to do yk
No this method of P & B is easier we have to just put the values
Tyyyy i understood and tried t9 do it by this method and surprisingly is quite easy!!
Dude even a 8th grader can do that with basic trigo knowledge
@real sentinel we studied trigo in 10th for the first time
that's wierd
That's CBSE 🤣
But in exam you will have to use a constant while calculating H
I need to learn trigonometrie. Currently I am a high school student. At school we are reviewing trigonometrie but the teacher is not explaining it. I want to learn Trigonometrie from starting, so can someone recommend me any youtube video or help me?
This trigonometry video tutorial explains how to evaluate trigonometric functions of any angle such as acute angles or special angles. It shows you how to find and use reference angles and coterminal angles to accomplish such a task as well as converting between radians and degrees as needed. This video contains plenty of examples and practice...
anyone in here?
No
anyone else?
If u have a doubt just send it
What is the relations between angles measured in radians and degrees
it got sum to do with sinus
like beginner type stuff
Radians and degrees are like fahrenheit and celsius, systems to measure angles
180° = π
90° = π/2
And so on
yea I know that Im just trying to understand how do the degrees corrilate with the sinus function
nvm I found that shi
Dude wrong channel
Can any1 help me w this question
you don't do this question because it's wrong
one of those plus signs should be a minus sign
Sry wrote the question wrong, this is the right one
the thing you have to prove has $m^2+n^2$, and you're given $m, n$ explicitly
Civil Service Pigeon
so you might as well calculate m^2 + n^2 directly
But how
Im confused like by using the identities or
show me what you have so far
I didn’t do anything so far..
you didn't even substitute in the expressions for m and n?
square and add both equations bro
Wait whole sq both eq and add them i did now
Just square both sides of the equations and add both of them
Or search it on Wolframalpha
thats rlly funny lol the heck
Also, for the record, when someone writes they want something quickly, helpers are suspicious that it might be an exam and hence they're less prone to help
ah makes sense
wait an exam on saturday
i guess maybe for the home schoolers, but nah im just doin homework
Seeing sen feels criminal
it's just spanish or portugese
HAHAHHAH
HAHHA
YK WHAT HAPPENED
SO I WAS DOING MY AOPS HW
AND ONE OF THE PROBLEMS WAS RLY WEIRD AND SMTH AND I ASSUMED SOMETHING AND GOT IT RIGHT
RAHHHHHH
Peak
If I see that on any math exam, I am walking out the door.
🗿 🗿
Square the given 2 equations on both sides and add them up... Use the rule sin^2x + cos^2x =1
Easyuyu
Let A be a finite set of points in the plane, no three of which are collinear. Assume there exist two triangles, each with vertices among six distinct points of A, whose intersection forms a hexagon that contains no points of A either in its interior or on its boundary. Prove that A contains a convex hexagon whose interior is free of points from A
help me solve this problem
Ahhh
I didn't see ur answer
I just scrolled to the question
But the solution is so general
U don't have to think for such kind of proofs
help can someone psl help me with this
2 is constant so take it out... Now take cosec^2x as -(- cosec^2x).. reason is bcz derivative of cotx is - cosec^2x... Now assume cotx as t so -cosec^2x dx becomes dt
Change the limits
When cotx= t at m t will become cotm and at π/2 t will become 0 as cot π/2 is 0
Now integrate t and put the limits
So i guess m should be cot inverse √2
omg thank you so much
can someone help me calcualte the orthocenter for a triangle with the corrdinates A (-2,1) B(0,-2) C(5,-2)
let the coordinates of the orthocenter be H(x,y) and notice the dot product of orthogonal vectors is 0
what does that mean
I'll tell u a simple way
Consider orthocentre as H (x, y)
yes...
m should be π/4 or 3π/4 or -π/4
Or
Consider line AH perpendicular to BC
Bcz lines passing through orthocentre are perpendicular to a side of triangle
yes
So the product of slope of AH and BC must be -1
they go through the vertex and perpendicular to the other side
That's property
Yep
multiply slope?
Yepp
Product of slopes of perpendicular lines is -1
Remember the product of slope of 2 perpendicular lines is -1
So do this for AH BH CH with respective sides of triangle
U will get 3 equations
2 variables
Solve n u will get answer
can anyone let me know if im missing anything for linear equations and slope of lines ect,? i have the formulas but i struggle with the questions anyhow. I either cant figure out what the question wants, or when i do the question i misunderstood the concept and i try to stick to the formula too hard and end up getting it wrong due to missing something small, any details i need to know
From what I see, you have all the notes/formulas for highschool linear equations, the tiny mistakes and rigidity of using the formulas is more of an experience thing, I say just try to figure out what tiny mistakes you keep making/struggling with, and do questions with them until it's memorized
alright ^^ thank youuu I'll deffo do some practice questions
Np!! Gl! Feel free to ping me if u need help with anything like this lol, I can't help with anything university level, but most highschool stuff I can help with
Guys , the question says that I gotta use elementary concepts , but it is way longer, is there any shorter approch, that uses conceptually high topics but get me answer in less steps?
Uuuh, for elementary are we counting sine and cosine laws?
Nvm, you need side lengths for those
And honestly there might be, I'll look into it
Yea I think there's just a lot of steps given the questions limitations
nah, just similarity, Congruency, ASP, and basic things
yeah sure, go ahead inform me once you have found it
that is why i was searching for an alternative way to do it shorter doesnt matter if it is conceptually high
do some
auxillary constructions
this is a famous problem, idr the name tho
Langley's adventitious angles
substitue cotx as t
Use the sum of angles of the triangle is 180° and use the exterior angle property...
You can easily let AB = 1 since scaling the figure up or down does not change the angles
true
Can any1 help me w this que, i divided both numerator and denominator w cos theta and applied the identity in numerator but im getting tan theta + sec theta at last but i should be getting 1/sec theta - tan theta
you got LHS = tan + sec
now multiply it by tan-sec in numerator and denominator
@tropic cairn
It's beyond my level and the hand writing 💀
Rationalise
is trig is eazy?...
kinda
Yes but sometimes it is hard
If you have to transform because there are many possibilities of a single question
But what does it requires to first jump into trignometry?
#geometry-and-trigonometry message
That's the answer to a very similar question
is khan academy is much better than Phsiycs wallah and Icse wallah in youtube?for maths?
Can anyone help me w this que i cant do it after the last steppp
If u get the flow of the identities and like know where to apply each, then it’ll be pretty easy, but practice is needed
.
Dude just separate the terms first
Write tanx/sinx *cosx separate
And cotx/sinx*cosx separate
it's easy than as hard it seems
No it's easy
In this question if you simplify RHS one step you will get the same
Anyone around who'd like to walk me through some problems in coms? first time here sorry if this isn't how you're supposed to request aid! I'm more a audio/visual learner
Post ur question
Here
If anyone knows the answer they will respond
I don't know what they are 😅
Khan Academy is very good for understanding concepts but it doesn't follow your syllabus and also doesn't provide you notes that will help you in your exams so if you have issue in understanding any topic, you can go to khan academy, search that specific topic and clear all doubts. But if you are studying for an exam and want to only learn what's needed PW and others are good.
PW will provide content focused on your exams and khan academy is just like collection of knowledge, if you are interested and have time apart from your normal studies you can look at khan academy to clear concepts.
You can do it after using the Monsky transformation.
Even using trigonometry it will be complicated, but you could guess the value of the angle if you use the Monsky transformation through a cyclic quadrilateral and then the Langly adventitious angles, but you need to know if they are the general cases and also, if it meets the degrees of freedom to verify if there is only one value that meets the conditions.
by congruence it comes out 20
cyclic quad?
but one angle is 40 and other is 30, it should be equal (from same base) to construct a cyclic quadrilal
does it takes long steps?
you have to build the cyclical
more or less
.
?
what is cyclical ?
inscribable quadrilateral
Here is the solution to the problem
let me take a look
that IS the Long way i was taking earlier
i already know that, but it is very tedious
Yes, but it is the most formal way. Another way would be with the Monsky transformation, taking the initial figure to another where you can use Langley's adventitious angles and you will notice that we are talking about an 18-adventitious triangle. You test the values and you get to 20...
this is my handwriting at its BEST what do u mean 🤬🫵
I mean it's my dream to write like that
Sorry 😔
You are elder sorry 😐
are there any rescourses you guys could recommend to learn geomatry as a full course online?
KhanAcademy is good for highschool level stuff, and afew of the lower level college stuff #book-recommendations is good for textbook resources as well
thanks :D
I'm in gr6 and I js learned sin cos tan :))
Its rlly hard lmao
I was wondering if anyone here goes to spirit of math?
Everyone who helps here knows math obvious
Nah I m indian and turned 15 2 days ago
you're in grade 6?
... how old are you
11
😭
Ok look
I am currently doing trigonometry
Qnd I was wondering the purpose of sin cos tan
Their ratios between the angle and side lengths of right triangles
For example, let's say you have a 45-45-90 triangle
Given one side length, you could find the lengths of all the other side lengths using sine, cosine, and tangent
https://www.mathsisfun.com/sine-cosine-tangent.html
Check this place out, they have an interactive triangle thing (idk what to call it lol), that shows the relation of all sides as you increase/decrease angles
ok yeah im really sorry but you're too young to even be on discord
<@&268886789983436800> underage
they're standard ratios between different side lengths given the same angle (think about triangle similarity). but yes we can't have you here, sorry. good luck. feel free to come back when you're 13+ or the legal age in your country.
Wait it isn't 13+ across all of discord and changes depending on country?
Never knew that
iirc the 13+ thing is global to discord
yeah there's a whole breakdown https://support.discord.com/hc/en-us/community/posts/360050817374-Age-restriction but they're all ≥ 13
Gotcha
If you are asking about what’s useful about them:
In principle you can calculate any angle using them, it’s just the algorithm for doing so is tedious and not taught in school, so most often you’ll see only exact values like sin(30deg)=0,5 etc., and maybe at some point a look up table with values for random angles (like 1 degree, 2 degrees…)
Another useful thing about them you’ll learn is trigonometric identities, useful in geometry problems (like double angle, half angle, etc.)
probably soon to be 17+ in Australia 
Damn really?
depending on how they classify it wrt social media
Yikes, I hate all ts going out, but that's not a convo for here lol
i guess i would say sin/cos/tan let you translate angular measurements into rectangular measurements
but i don't think any of these answers really explains why they're useful
Yea, it'd be best to just showcase the real world uses of them ig
Not just "oh it works because xyz" and instead the actual applications of them, but ig its too late for that lol
Anyway, I also got questions xd
How the hell do I transform sinusoidal waves- I'm teaching myself this stuff because teachers are all unavailable for the next few weeks to months and have 0 clue what I'm doing (textbook also doesn't really explain it well)
So like usually you'll take the equation y=sin(x) and transformations turn it into y=a*sin(k(x-c))+d
so like a transformation is a procedure that eats an equation for a function, and spits out a new function, where you've changed the graph of the function in a certain way
so translation upwards 5 units would eat say sin(x) and spit out sin(x)+5
and if you plot the grpah of y=sin(x) and y=sin(x)+5 you'll see the second graph is the first one shifted up 5 units
so the important thing is to understand what the transformation you're applying does to the functions it eats and then do that to your rule
Oh, so it's literally just linear or exponential transformations, what if it's inverted? Same theory as linear or any other graph?
Sending query to Wolfram Alpha, please wait. 
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The error has been reported and should be fixed soon.
If the error persists, please contact our friendly support team at our support guild!
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Do any of you have recommendations for resources to learn these topics, like a good YouTuber or something?
-
Trigonometric formulas for a single angle
-
Sine, cosine, and tangent of the sum and difference of two angles.
Double-angle formulas for sine, cosine, and tangent -
Solving trigonometric equations
-
Solving trigonometric inequalities
For which class ?
11th ?
KhanAcademy for basically anything below university level, they have lessons and quizzes there too, The Organic Chemistry tutor on YouTube also has great videos
What is Khan academy? 😅
Interactive course thing for basically anything math/science related, they have great videos in there, with practice quizzes/tests and walk throughs for stuff you struggle with, they don't have anything past 1st year university, but it's an amazing free resource
Oh 😮
I will also learn from them especially physics and maths
Yea they're great, lemme take a ss
Ss of what ??
Here's their physics modules
There's more as you scroll down
But yea
Great resource
Thanks again hope i could also help
If you need in idk something I can help you in 🥺
How good are you with sine waves and precalc?
I m in 10th 🥲🥺🥲
All good then lol dw
Ok 🆗
Does anyone have tests or like good excersises for derivatives of trigonometric functions
I would do it by compound angle and double and triple arc identities, but I don't know Moivre's theorem.
sen 5x = sen(3x+2x)
You know de Moivre's theorem?
Use the theorem then Substitute n=5
Expand the left hand side and separate the real and imaginary parts. Then express everything in terms of sine theta only.
Moivre's theorem is for number complex, sure?
Yes but it can be used to derive trigonometric identities for real angles.
Bottom line: it's an ironic theorem
Ty nwn
np
can anybody help me study trigonometry easily (Im a machining student)
If you prefer watching YouTube instead of books https://m.youtube.com/playlist?list=PLhSQQGbiWoTChZSbP-XcXH40IT7vfyyFk
I recommend this one: https://youtu.be/mhd9FXYdf4s?si=MtURf_8IpejY2tzf
A trigonometry introduction, overview and review including trig functions, cartesian quadrants, angle measurement in degrees and radians, the Unit Circle and the Pythagorean Theorem.
UPDATE: I have posted a longer multi-part trig series! Please see the Introductory video here: https://youtu.be/U23JMdBIJ0M
The playlist is here: https://www.you...
Ill take books aswell
I'll let someone else recommend as I've not read them
oh alright but thanks for your help
Guys
when proving something of euclidian geo using analytical geometry
how do you do?
like, I need to prove the angle bisector theorem using analytical geometry
and I'm trying to do so using the equation for the angle bisector line
but it has so many things to take into account, like if the eq is of the form Ax+By+C then if C is negative then my eq becomes negative
and so
try to set up an equation
It's often a great help to choose the coordinate system cleverly.
In case of the angle bisector theorem, everything becomes much easier if you pick a coordinates such that the angle bisector is the y-axis. The slopes of the other lines now end up having very simple relations.
yeah?
but the conditions about the formula for the angle bisector line don't affect?
That's what's been puzzling me
Like I can just say "I got this triangle but I don't care about where it's located in the plane, as long as it's a triangle I can choose my coordinate reference"?
and place it as I did in my proof?
Yeah, that’s what I would do.
Okay, ty
I mean it makes sense but we didn't see the topic with the teacher
and now I got an assignment that's like 100% of my first unit
bc he didn't want to check homeworks
he also said not to cheat but we could use the book
It's up to you whether you have more purist ideals about what "using anslytic geometry" requires here...
But in this particular case the win from a well-choosen coordinate system is huge -- each of the two ratios in the theorem rurns out to equal |x1|:|x2|.
I don't know what that last thing is but ty
The ratio of the absolute values of the x-coordinates of the two other corners in the triangle.
here sin(x)^2 + cos(x)^2 = 1 hehehe thats all you need to know
Hello chat
Let A(0,0) and B(0,6)
sqrt(x²+y²) = 3sqrt(x²+(y-6)²)
x²+y² = 9(x²+(y-6)²)
x²+y² = 9(x²+y²-12x+36)
x²+y² = 9x²+9y²-108x+324
8x²+8y²-108x+324 = 0
x²+y²-(27/2)x+(81/2) = 0
This is the equation of a circle with centre (a,b) = (-(27/2)/-2,0) = (27/4,0)
a²+b²-C = r²
(27/4)²+0²-(81/2) = r²
(729/16)-(81/2) = r²
r² = 81/16
Area = pi * r² = pi * (81/16) = (81/16)pi inch²
why into geometry and trig


