#geometry-and-trigonometry
1 messages · Page 125 of 1
What are some tips on trying to locate trig functions
Ik radius or hypotenuse will not be negative
Like this example
Radius and hypothenuse refer to lengths, hence they can't be negative indeed
Yeah what about that?
Ohh I see
Like I’m confused which quadrants are they in
Honestly I don't know which triangle they are talking about
Well, you are given that cosine is negative, so which quadrant can it be?
3rd
Oh btw their coordinates are (cos(theta), sin(theta))
1: (+,+), 2:(-,+), 3:(-,-), 4:(+,-)
Awesome, that's the only thing you need to remember (not strictly by heart of course)
2nd as well
cos is negative, sin is positive
Will it apply on reciprocal?
Huh?
Csc, sec, cot
The reciprocal of a negative is negative and the reciprocal of a positive is positive
Will it still imply the rule
Don't you know this? 😅
I do
Then what's the issue? Sorry I'm not getting you
Will it look like (sec(theta), csc(theta))
What is it?
I really don't understand what you're talking about
On the Cartesian plane? Then no,
I mean that
(cosθ, sinθ) is not at all equal to (secθ, cscθ)
What will it equal to
Is it (1/x, 1/y)
Sure
I don't know, I've never done such exercises honestly
Is it normal to be confused on it
I guess so
I mean, it is much more common to be confused in trigonometry than in, let's say, log and exp
Ik that
At least form my experience here and in my real life
And got 100 and master it
On the other hand, I personally was way more confused in probability and combinatorics than in trigonometry, but I believe it depends a lot on the person itself and especially on how the teacher explains the topic
Now what happens if I want to see which quadrant are sinθ=.5 and cosθ=-4.1 in
None
I love math
Why
dms
oooh noo not the dm'sssss brooo
Prove that sum of 2 sides of a triangle is larger than half the median PLS HELP
Could you do a contradictive proof?
Suppose that half the median is larger than the sum of 2 sides of a triangle
Do the working until it contradicts?
Hmm
oh lemmetry
Reposted here: #help-14 message
Ah kk
ok time to derive half tan identity
tan(2x)=2tan(x)/(1-tan^2(x))
=> tan(2x)(1-tan^2(x))-2tan(x)=0
=> -tan(2x)tan^2(x)-2tan(x)+tan(2x)=0
i dont like negative coefficient so
tan(2x)tan^2(x)+2tan(x)-tan(2x)=0
tan(x)=(-2 +/- sqrt(2^2-4(tan(2x))(-tan(2x)) ) / (2tan(2x))
= ( -2 +/- sqrt(4+4tan^2(2x)) ) / (2tan(2x))
= ( -2 +/- 2sqrt(1+tan^2(2x)) ) / (2tan(2x))
= ( -1 +/- sqrt(1+tan^2(2x)) )/tan(2x)
=(-1 +/- sqrt(sec^2(2x)) )/tan(2x)
now since theres a +/- i think the absolute value isnt necessary
= ( -1 +/- sec(2x) )/tan(2x)
=-cot(2x) +/- csc(2x)
so im assuming youre supposed to use the positive root maybe?
so
csc(2x)-cot(2x)=tan(x)
therefore
tan(x/2)=csc(x)-cot(x)
why is there a frowny face
ok anyway lets check now
YESS
i wonder why it cant be the second root though
ok now cot(x/2)=1/(csc(x)-cot(x))=(csc(x)+cot(x))/(csc^2(x)-cot^2(x))=csc(x)+cot(x)
so cot(x/2)=csc(x)+cot(x)
wait a second if theres a half angle identity does that mean theres a one third angle identity
(cosx+isinx)^3=cos^3(x)+3icos^2(x)sin(x)-3cos(x)sin^2(x)-isin^3(x)
=> sin(3x)=3cos^2(x)sin(x)-sin^3(x)=3sin(x)-3sin^3(x)-sin^3(x)=3sin(x)-4sin^3(x)
=>4sin^3(x)-3sin(x)+sin(3x)=0
cardanos formula would be perfect but damn it i havent learnt it yet
i does its the median formed by the 2 summed sides to the third side
\text{ If two tangential lines TP (t being the point of intersection} \\
\text{ between x-axis and the line)} \\
\text{ and LQ (l being the point of intersection between x-axis and the line) of} \\
\text{ a circle make points P and Q such that PQ is an arc, and TP makes an} \\
\text{ angle of $\psi$ and LQ makes an angle of $\psi + \triangle \psi$. Here, angle } \\
\text{TPL would be $\triangle \psi$. If we make enough lines, then a Kite would } \\
\text{ be formed with unequal angles x and $180 - \Delta \psi$. If someone could} \\
\text{ please explain how x would = $\Delta \psi$, it'd be huge.}
inheritance.
enjoy
what are those
presumably because they want you to pull all perfect squares out
can anyone help
Asking the actual question right away is more likely to get responses.
Asking "Can I ask...?" or "Does anyone know about...?" doesn't give people enough information to decide whether they can help, and answering can feel like a promise to help with the actual question, which they might find themselves unable to.
Try simplifying
(8 = 2 * 4 & 4 = 2*2)
so instead of 3√8 its (3*2)√2
so 6√2
and approx 6√2 via Newton's method (A friend taught me)
pretty sure they are asking just for the radical and not a decimal
yea its right thx bro
Or you could ust use a calc and understand, somehow
Yeah, so i in Algebra II, we learned about the 6 (We learned about really 9) of the trig functions. What are all of them???
I know of:
sin(
cos
tan
asin
acos
atan
sec
csc
cot
sinh
cosh
tanh
sech
csch
coth
asinh
acosh
atanh
and exsec
excsc
versin
haversin
and chord
what are the others??
alr bro ima add u
nah like as a dm
@everyone
@glacial pelican
so, my pfp has a unit circle with tan, cot, etc. on it
I just don't understand their relationships
this is a 45-45-90 triangle
if each side is x, the hypotenuse should be x sqrt 2
that means 100 = x sqrt 2, if you can solve for x, you've got the answer
Yes….
so the answer is 50 sqrt 2 as
45-45-90 triangles use
x to x to x sqrt 2
as the ratio of their sides
Trig question!
(Trivia)
probably around 56
it's like 55.99 or something right
Ill check
I’m a little confused
I may need
Simpler terms
I have the flu rn so my head is spinning
What is 45-45-90
A right triangle with angles of degree measure 45
so 180-90
-45
= 45
so the 3 angles are 45, 45, 90
the name is 45-45-90 triangles
this is one of the special right triangles
so it maintains a consistent side-to-side-to-side ratio
which is:
x to x to x * sqrt 2
given that the hypotenuse (longest side) is the x*sqrt 2 side
oh ok
dang i just realized you have a unit circle pfp
must really like trig
wowzers I could actually learn using ths
trig is not fun once it gets advanced
also everything connects to the unit circle which is also not fun
I have to turn stuff like (1+cos(x))(csc(x)-cot(x)) into one trig function or constants like sin(x) for this specific problem
i havent gone to learning trig yet
so im probably fine for a few months
The hell could something like sin^(-1)(B) mean. Will it be the same as 1/sinB?
Got curious about trigonometric functions and wanted to put a negative power on one of them
Because like. Sin^2(B) => (sinB)² so shouldnt it be the same with sin^-1(B)?
the notation is not consistent
the exponent in sin^2 refers to multiplication, whereas the exponent in sin^(-1) refers to function composition
uh huh 😭. So what does sin^(-2)(B) mean
or is that even real
at all
wdym function composition ?
calling $f^2 = f \circ f$ and so on
cloud ☁
whts f o f
ig it's that : https://www.youtube.com/watch?v=ZFPkQkURSxk
This algebra video tutorial provides a basic introduction into composite functions. it explains how to evaluate composite functions. This video contains a few examples and practice problems.
Algebra Review: https://www.youtube.com/watch?v=i6sbjtJjJ-A
Join My Newsletter:
https://bit.ly/4jUXp6M
Func...
ima watch
so just to be clear. 1/sinB = (sinB)^(-1) and not sin^(-1)(B)?
yes
kk 👍
Really I think we should just use arcsin or asin to denote the inverse functions to avoid ambiguity
these are trigonomertical functions made for 1/sinx, 1/cosx, 1/tgx, 1/ctgx
for 1/sin is arcsin, 1/cos is arccos, 1/tan is arctan and 1/cot is arccot
but you'll barely use it in school
because in most cases you'll need a calculator, which is mostly forbidden when learning math
and while doing an exam
Isnt 1/sinx = cscx?
Yo this is straight cap bruh
1/sin is csc
1/cos is sec
1/tan is cot
i said i made a mistake
I mean w8th how much trig traumatizes people. You really can't forget something like this can you 😭
arcsin is the same thing as inverse sin, arccos is the same as inverse cos, etc
just different names
isnt
1/sinx the inverse of sinx
im talking about the function inverse
oh
1/sinx is called the "multiplicative inverse" of sinx
but if you have $f(x) = y$, the inverse function $f^{-1}$ satisfies $x = f^{-1}(y)$
you'll learn about this in algebra
Altanis
so for example sin(pi/2) = 1. inverse sine should take 1 and give pi/2
i.e., it should undo what sine does
oh
ok so it just gives you the radians and their measurments
arcsine takes a value and tells you what angle, when you take the sine of it, gives you that value
arcsin(sin(theta))=1
"(sine) calculates a ratio of triangle sides (opposite/hypotenuse) based on an angle, whereas (inverse sine or arcsin) calculates the angle based on a given side ratio. takes an angle input, while takes a ratio between and to produce an angle (usually in degrees or radians)."
can somebody help me with this?
im on my last try
i believe y is 7.5 and x is 7.5sqrt(3)
As a helper, please do not give out answers that could be copied as a homework solution. Have the student work through the problem themselves and guide them along the way.
do you know about trigonometric ratios? And what they would be for the angle made between the side 15 and x
not really. I've been sick with the flu all week so I don't really know what's going on.
hope you get well soon.
anyways. a right triangle has some ratios between the non-right angles, these ratios are known as trigonometric ratios. the ratios for an angle theta are as follows -> sin(thetha) = opposite/hypotenuse
cos(thetha) = adjacent/hypotenuse
tan(thetha) = opposite/adjacent.
there are also sec(thetha), cosec(thetha) and cot(thetha) which are 1/cos(thetha), 1/sin(thetha) and 1/cot(thetha) respectively.
But for the question, only the highlighted ones are necessary
let me make a diagram to explain better
lets call it angle A for simplicity. Using the ratios for sin(thetha) and cos(thetha) above. try to find the ratio for sinA and cosA.
This similar method can be used for the question.
This similar method can be used because sin(30) and cos(30) have some value
1/2 and sqrt(3)/2 respectively
should be enough of a hint?
feel free to ping me if you find any difficulty.
i will try my best to clear that doubt
Uhm
Okay
So
So would I use tan
Then
I’m confused
Like
If I need to find X
What am I trying to find
It’s the hypotenuse right
I don’t really understand what tan, sin, or cos are
I was there for the introductory lesson
That was it
theyre the ratios of the side of a right triangle
search up 30 60 90 triangle
no you cant use tan here. tan(thetha) = opposite/adjacent. the opposite and adjacent of the angle are what we are trying to find.
ratio is x, x(sqrt(3)), 2x
oh mb
well i aint typing all that so uh
As a helper, please do not give out answers that could be copied as a homework solution. Have the student work through the problem themselves and guide them along the way.
thats why
nah its good enough
ok how do i explain the core concept of trig to someone more better
youre trying to find the base and perpendicular of the triangle in your question
the hypotenuse and one of the angle is given
which trigonometric ratios use the hypotenuse in them?
try to use that on the 30 deg angle
No it flipping doesn’t cus idk what the hell that mean chat
Hate to break it to you
they just mean the angles of the triangle. 30-60-90 degree angle triangle
Okay
So
Do I need to apply that to this equation
I googled it
It says like
A ratio
no you dont need to
Okay but
How do I know what I’m solving for
I don’t understand that
If I understood which one I need to use
Id know how to solve from there
But I don’t
30 is the measure of the angle between the side 15 and x right?
if i treat 30 as A.
yes
then what will cosA be?
if
-> sin(thetha) = opposite/hypotenuse
cos(thetha) = adjacent/hypotenuse
ok what will be the side adjacent to that angle?
which ISNT the hypotenuse
So it’d be x
which ISNT the hypotenuse
yes
now
the trig ratio for cosA is adjacent/hypotenuse
so
what is the hypotenuse?
15
ye
because thats the angle we are working with right
so that measn
cos(30) = x/15 where adjacent and hypotenuse are x and 15 respectively
rearraging to isolate x. we get cos(30) x 15 = x.
now cos(30) has a specific value of sqrt(3)/2
so plugging that in and solving for x
we will get x.
similarly. try to use the sin of the angle
Ah okay
I see
Don't troll!
Hi, I made this unit circle diagram for my obsidian notes. What do you think is it clear or too complex?
I looked at many examples in google images and tried to make something between table and radial diagram.
Not gonna lie, it's amazing. Looking good. And yeah, it's clear for all basic value. Maybe you can also make a diagram with all the trigonometric ratios on the unit circle ? But other than that, great work !
Thanks!
Maybe you can also make a diagram with all the trigonometric ratios on the unit circle ?
Can you elaborate on what you would add? I looked a bit, and notice that tan, cot, sec, csc can be also added, but I am thinking about showing them in a separate table below.
hello
I would add The basic formulas of tan, cot, sec and csc in terms of sin and cos and also I don't know which visualization you watched. But I would prefer the one in which a tangent is drawn from the point (cos(theta),sin(theta)) and let it cut the x axis and y axis and the two segments separated by that point are tan and cot (that's why it's called tan!) Honestly, it looks cool and also neat, another way is to also draw a vertical tangent at the point (1,0) and let it intersect the extended radius but I don't think in that version, cot will look so aligned with tan
In the version I suggested, all the co- ratios like co-sine, co-tangent and co-secant will sit on the complementary angle side of the theta.
Can somebody help me with this problem?
Your side a=4 and angle A=30 degrees, whilst side b=x and angle B=60 degrees. Both sides are opposite to the angles, so you can apply Law of Sines to this problem
Did you try using Law of Sines?
ah oka
i did not
Oh wait
it's essentially a pattern matching exercise
I didn't notice it was 30-60-90
Yeah your point makes more sense than mine
My bad
im just confused like
what i do
after i know that
though
like
im a bit overwhelmed beecause i missed almost all this week of class so i know very little about whats going on
Rules for 30-60-90 triangle are, that Short leg (opposite to the 30 degree angle) = s, Long leg (opposite to the 60 degree angle) = s√3 and Hypothenuse = 2s. You can apply this rules to any 30-60-90 triangle and they will work for each of them.
In your situation s=4
use a different variable
Can anyone help me with sorting triangle congruence theorem examples?
These four examples i categorized it as not enough information
ok
I posted this in the help forum
You have to prove if each triangle is congruent or not and i selected all of this as not enough info for congruence theorem but i dont know if its right
Come in forum
Ok
does anyone know how to use eulers spiral to optimise racing line
15 times sin(30) then that's y then do a^2 plus b^2 = c^2 for x
use sine and cosine
Hi! I am new here.
Could you help out with some trigonometrical sums I have some difficulty in?
I am in Grade 9.
The 16th and 17th.
no way this is 9th
9th?
Sure
Maybe she's preparing for some olympiads
.... No.
Its school
Lmaooo
Where are you from?
India
Wth
Yep
There are worse sums-
Yes
Makes sense
In state boards this level aint even in 10th
thanks♥️
Uhh... Suppose i need help with Theorems on Area and Mensuration.
Where am I supposed to write?
for 16:
cos²(45+theta)
= ½(1+cos(2(45+theta))
= ½(1+cos(90+2theta))
= ½(1-sin(2theta))
cos²(45-theta)
= ½(1+cos(2(45-theta))
= ½(1+cos(90-2theta))
= ½(1+sin(2theta))
tan(60+theta)tan(30-theta)
= (sin(60+theta)/cos(60+theta))
(sin(30-theta)/cos(30-theta))
= (2sin(60+theta)sin(30-theta))/(2cos(60+theta)cos(30-theta))
= (cos((60+theta)-(30-theta))-cos((60+theta)+(30-theta)))/(cos((60+theta)-(30-theta))+cos((60+theta)+(30-theta)))
= (cos(30+2theta)-cos(90))/(cos(30+2theta)+cos(90))
= (cos(30+2theta)-0)/(cos(30+2theta)+0)
= cos(30+2theta)/cos(30+2theta)
= 1
so the denominator evaluates to 1 thus we now only need to care about the numerator
cos²(45+theta)+cos²(45-theta)
= ½(1-sin(2theta))+½(1+sin(2theta))
= ½(1-sin(2theta)+1+sin(2theta))
= ½ • 2
= 1
Thanks♥️
you're welcome
Even though im also icse I never had these
exactly
HOLY
This makes me feel dumb
and I finished my unit on geo trig..
😭
........how.
If you want to know the explanation for denominator step
Go ahead
thanks i got it
There's misprint in Q17's first part
I'll do the other two
SAT identity?
For trig
I’m just did that
Just by drawing triangle
And subtract by 0,90,180, or 360
To get to 30-60-90 or 45-45-90
Nah I remember it by even and odd multiple of 90 and for sign conventions take help from STSC rule
If it's odd then the function will turn into the opposite one
If even it will remain same
i just remember bcs the sine and cosine functions are pi/2 from each other
tho i haven't taken the sat yet igs so idk how important most identities are
yeah that will be 2A
sorry i forgot to mention it-
Q17:
There are many methods by which I solved but I'd go with easier.
B) tan(2A)= cot(A-18)
WE CAN USE THE IDENTITY tan(90-A)=CotA
=> tan(90-(A-18)
=> tan (108-A)
Now, tan(2A)=tan (108-A)
2A= 108 - A
3A= 108
A= 36
C)Sec(2A) = Cosec(A-27l
Cosec(90-2A)= Cosec( A- 27)
90-2A= A -27
117= 3A
A=39
Eww it's soo hard to type
As a helper, please do not give out answers that could be copied as a homework solution. Have the student work through the problem themselves and guide them along the way.
Oh okay
Just use trigonometric functions of allied angles
thanks i appreciate it
and...my earlier question. where do i ask if i want help in Theorems on area and Rectilinear figures?
You can ask here?
But it's better if you ask about the method or idea
Go ahead
yeah yeah'
that only
im capable of finding the answer
some sums are a lil tricky
a sum of money placed at compound interest doubles itself in 5 years. It will amount to 8 times in -------- years.
how to find this out-😭
what sums are these😭
oh no i mean the entire server. so many rooms!
(one problem i did by college board had like a 30% interest rate or something... anyway)
so, lets make the sum of money a, and if it doubles itself every 5 years.. a(2)^x would be if it doubles every year, so to make it five years, at five you want the exponent to be 1. so x/5 for the exponent
and, you want it to be equal to 8a in some x amount of years
so divide out the a. does that make sense? i think thats what the probem is asking... if it is what the problem is asking i think you can figure it out from here
yup
Thanks
One angle and side are given... But the other is not.
So
Ig this is ASA
I am not sure tho
Which example?
The first one
I think its the first.... SSS
How come
Oh wait i maybe wrong wait
I’ll recheck the first one
Yes
It is the first one in SSS
This is what i got from it
It tels us UX And VW are congruent
Y is midpoint of UW and VX so those two sides bisect
Hmm..
Its confusing
All of them seem to be correct-
I have to do this ig
Can u wait?
is there a wrong one in all categories all the sss one look right to me
I am currently doing a sample, so i may not reply so quickly
Ik... Thats why...
I thought it was the first one as per the instructions but it cant be-
Yea
Wdym?
Wait
All the SSS catagory figures are correct
May I ask, which standard is this?
Standard?
Which grade?
10th
i think maybe this one
is ssa instead of aas?
SSA is not a congruence theorem
nvm oops (srry i haven't done ts in a while)
It’s fine this stuff is weird
yeah lol
100%
I am doing a maths sample
I may have to ask questions too-
Its a little confusing
whats a sample if you dont mind me asking?
like... a practice test, or something?
ooh i see! depending on what grade level type stuff i can try to help... good luck~
i am ninth
and i have doubt
the question is
if x=7-4root3, find the value of root x + 1/root x
like uh
this?
or is 1 not under the root
yea
so, first step i'll give you is 7-4root3 isn't an easy number to work with...
...so, try to express it as a square of an expression
then, you can easily write it and square root it to that expression...
make sense?
if you're still stuck, i can give you the square of the expression to help
Like ah

yeah?
how can you make x into that form
.....
the expanded form is a^2+b^2-2ab, so lets say 2ab is 4sqrt3
and a^2+b^2 would be the 7... so how could you simplify it
hi there.
hello
hm yes
so what would a-b be hmm

yupppp
after you plug it in its just one more "big" step (to simplify 1/sqrtx) and it should come out as a nice clean number
I FEEL LIKE EINSTEIN-
you guys look like a couple of Einstein brains.
yayyy
thanks evelyn!
phew i wasn't sure what grade you were so i was hoping i wasn't overcomplicating it lmao
nope i understood
yey xd glgl with the rest of the.. sample
lol
yeah
may i share my question.. uh
?
ok
yup~ for sure
me will try to solve-
yay!
me will try to solve too~
CIRCLES!
Angle BAC=90° btw.
alr
radius not given right?
so to clarify, between o and c is 5, c and f is 4? and is that other value up there...8?
we can find it actually, 5+4.
yeah
OC=5, CF=4.
is o the center
original question is this, if you wanna take a glance.
ah thanks\
oh, so i guess o is the center
yup.
bon aphetit!
genius.
@burnt crystal @minor heron
Yeah?
Heres the forum for my question btw
I explained pretty much every example
So if you find something wrong you can tell me
Thanks
wait i think i fcked up now that im nit hungry ummm
lemme re-look

Guys i have my maths exam tmrw and im freaking out
hmm ah this problem might be a bit… above my level 😅
19 chapters.... 19 CHAPTERS😭
Noooo its okay 😭
it is for me too-
what are the chapters focused on
EVERYTHING MATHS HOLD
EVERYTHING
WHAT IS NOT THERE?
Ok imma sleep now
Its 4:25 am
My parents will kill me
Gn
Anyone know a good source of practice question for high school vectors? (scalar/vector proj. dot product, parallel perpendicular components, relative vectors, applications) stuff like that
mmhm khan academy was my goat in the past
had to be a bit picky thru lessons to find what i wanted but yeah
NCERT MATHS TEXTBOOK OF CLASS 11
yeahh
tho it doesn't go the most in depth iirc
haven't learned some of the stuff u listed so not sure if that'l cover, but i guess just look around
Thanks
no direct solutions please!
how did you know the angle DOC is 90°?
?
seriously?
and its already here


please speed i need this
Can anyone help me with my question? https://discord.com/channels/268882317391429632/1477193085623599134
Does this cover college mathematics?
If so, I did not take additional mathematics in school and I am currently spending 3 hours on an addmath homework. Is there any channel to ask questions?
Sure
Help me explain proof for volume of sphere
slice a sphere horizontally into slices
each slice approximates a cylinder
calculate volume of cylinder and then take integral
Are all of these ASA?
Which ones arent
Yes, all of them 👍
Are you trying to prove it?
looking for team mate to study geometry (i am russian but small speak eglish)
I have to put the examples in the right categories
Not Enough Information
SAS
SSS
HL
ASA
AAS
Ok
Do you want to see the rest of the categories?
looking for bro to study geometry together ( i am russian)
Geometry
I am in
I am also in Geometry
mm im not in geo im in precalc but i can help (tho i dont know russian)
Hello! I am trying to help my friend on inscribed angles, is there anywhere where I could find some practice problems
aops mentioned
i love aops for practice problems too
130
@exotic yarrow how often do u deliver mails
Am I wrong on this one?
20/360 isn't 18
Does anyone know how to solve theses sort of questions?
Oh
huh
I guess so, but you should provide a translation, at least for the exercise you have doubts on
ok tysm i will translate them
That’s good
But please don’t ping me unless you have a comment with actual substance
Yes that’s in the link
please don’t ping me unless you have a question or smt that’s not already answered by what I sent
What
well...my maths exam was today.
THE PAPER WAS HELL-
LIKE
SOME THEM ARE NOT EVEN IN OUR BOOK-
I want it
Can someone help me solve this i have a test in 2 hours
How do you know which angle you’re supposed to find
i'm not good at geometry, and this problem that I need to solve has come up.
Say the blue arch represents the path of a ball, the ball bouncing around this circle forever. How do I figure out which way the ball should bounce/reflect off the circle?
theres this one problem I have where its a 30-60-90 triangle with the shortest side being x-1 and the middle side being x, when I solve for x I get x=1 which would make the shortest side 0, how would I solve this
Whats your diagram?
Oh i see
The middle angle has the middle length send
And the hypotenuse is the longest
Oh waitp💀
I cant read
That kinda feels like giving the answer
Hello! can you answer one of my questions in precalculus chat?
im not really sure what counts as precalc cus i think thats more of a US thing and i live in australia, but if youve done college algebra i would assume they covered that sorta stuff?
kk, thank you!
Hey guys, please I need help on the question:
"Four angles of a pentagon are equal and the fifth is 60°. Find the equal angles and show that two sides of the pentagon are parallel."
How is it possible that 2 sides would be parallel?
kinda looks like that though i drew it horribly
you solve for internal angles to find the 4 congruent angles then use alternate interior to prove that the 2 sides shown are parallel
Thank you
How do I solve for x? b*b(x-d)=-1/b (x-1)
This is a glorified linear equation. Using the distributive property yields
$$b^2 x-b^2 d=-\frac{1}{b}x+\frac{1}{b}$$
Now, get your terms with $x$ on one side and the terms without $x$ on the other. Then divide by the coefficient of $x$.
Civil Service Pigeon
anybody have some cool / interesting 3d vector planes or complex numbers questions?
Consider a tetrahedron with two isosceles triangle faces with side lengths $5\sqrt{10}, ,5\sqrt{10},$ and $10$ and two isosceles triangle faces with side lengths $5\sqrt{10},, 5\sqrt{10},$ and $18.$ The four vertices of the tetrahedron lie on a sphere with center $S,$ and the four faces of the tetrahedron are tangent to a sphere with center $R.$ Compute $RS$.
thank you!
Civil Service Pigeon
wait no this is the shit one
oh like too easy?
it's just boring
oh alr alr
I mean feel free to do it if you want
u got any interesting ones?
thanks!
lwk preparing for my yr 12 vectors and complex numbers test lol
it's just standard vector lines and planes
and some supplementary links to complex numbers, simple trig and sequences/series
i lwk need help w this
Given a pyramid S.ABCD where the base ABCD is a rhombus with side length a and angle ABC equal to 60 degrees. The orthogonal projection of point S onto the plane ABCD coincides with the centroid of triangle ABC. (Let H be the centroid). Let P be the angle between the line SB and the plane SCD, Calculate the sine of angle P, knowing that SB = a.
i dont understand the 2/3 HK part much
,rotate
shouldn't H be inside the triangle ABC if its the centroid? isn't it like the intersection of its medians?
yeah thats what i was wondering
none?
gang?
if theres addision in a square root, you need to calculate it
but those are all the same answers
I was trying to solve for the hypotenuse but i've gone with something simpler instead
a^2 + b^2 = c^2
literally just the Pythagorean theorem
yes thats what this is too...
welp my bad
hypotenuse is c
yeah
u have rearranged the pythagorean theorem here
np
wizard hangout
Lol
I am right, rigth ?
yes
Thank you sir
Just started doing these I. Trig they go from that’s pretty easy to fuuu that
no need to call sir bro lol
yes this probably is level 1
Heyy this was in my exam!
We also had standard angles
Some of these are easier than others. XD
Like WAY easieer.
can anyone help
ikr
what do u need help for?
pythagorean triple]
a very neat triangle I came across when messing around with geometry
Yo that’s tuff bro
I would definitely recommend just sitting down with graph paper and messing with geometry. things like this seem to come up out of nowhere when you do that
can anyone tell me how to know if there are one or two or non ssa triagnels
this is gonna be on my precal test
also hwo do i do angular momentum
dyk the law of sines
heres a pdf if u wanna look thru this https://www.rit.edu/academicsuccesscenter/sites/rit.edu.academicsuccesscenter/files/documents/math-handouts/T7_AmbiguousTriangles_BP_8_17_18.pdf
its based on the angles and stuff
lwk idk its not on my precalc test i haven't done this since last year where i used ai to help.... guide my ah
idk what angular momentum is so glgl with that igs
yea its like sinA/a = sinB/b=sinC/c right
Angular momentum is the same as linear momentum but for angles
use this
Np
yeah
may I have help on this?
there should be a formula or smth right
I got 85and a half degree
howd u do it
How does line DC correspond with line BC
I checked once again I think I did wrong first time so i reattempted it and got 81° this time I dont know it's correct or not I solved this as shown in img I don't know weather this is the right method or not😅
Since ABC triangle and BDC triangle are similar triangle due to ASA criteria AC/BC i.e hypotenuse of triangle ABC and BCD is equal to DC upon BC i.e DC short side of triangle BDC upon BD short side of triangle ABC
Here you are getting confused because You have fixated that BC is hypotenuse of triangle BDC but you should also keep in mind that it is also short side of triangle ABC
Yo bro give answer I am curious
`
@fleet light here is another simple solution of ur problem
i guess it does coressponds bcz triangle DBC and triangle BAC are similar
by AA similarity
Any ideas why this is wrong?
Part ii where you have to find f(x) =0 is the problem
Because pi/2 doesn't work
,w true or false cos(2x+ pi /3) = -sin(2x+pi/3+pi/2)
,texsp ||Note that your $\theta+\frac{\pi}{2}$ is $2x+\frac{\pi}{3}$, so it should be
$$\cos \left(2x+\frac{\pi}{3} \right)=-\sin \left(2x+\frac{\pi}{3}-\frac{\pi}{2} \right)$$||
Civil Service Pigeon
another geometry thing
In geometry, a Heronian triangle (or Heron triangle) is a triangle whose side lengths a, b, and c and area A are all positive integers. Heronian triangles are named after Heron of Alexandria, based on their relation to Heron's formula which Heron demonstrated with the example triangle of sides 13, 14, 15 and area 84.
Heron's formula implies that...
Anyone understand the law of cosines?
Asking the actual question right away is more likely to get responses.
Asking "Can I ask...?" or "Does anyone know about...?" doesn't give people enough information to decide whether they can help, and answering can feel like a promise to help with the actual question, which they might find themselves unable to.
You can use laws of cosines when there is a SAS or SSS
lots of people yes
…
Well, he answered your question 😬
Not wrong
But yeah it's easier if you share a problem you can't do, or a question about it
What’s going on?
math
Hey I wonder what is borrowing in trig
my precal test went good
My math correct or I got to go back and relearn mathematical properties.
Well the process is rough...
And I don't know what you're doing XD.
Hey. Can somebody help me out here? This is on the review guide. When I did it, I got 9, not -680. What have I done wrong?
Umm...
689 - 680cos(x) $\neq$ 9cos(x).
Restarter
$689\cos(x) - 680\cos(x) = 9\cos(x)$.
Restarter
shes done 900-689
Yeah.
ahh ok
Find x without using trig I was told 😭
can a 3 dimensional frequecy table be used to display more complex data sets ?
No solution
use de moivre
?
Huh
Is it in Spanish
Hey can someone help me pls
I don’t understand the ambiguous case
<@&286206848099549185>
?
Could u explain the ambiguous case pls 💔
Wdym by ambiguous case
When ur trying to see how many triangles are possible given 1 angle and 2 sides
you could have been more specific and said it from the start
You can use similarity to solve this
Mb my teacher calls it ambiguous case so I js said that
I am doing sin(theta)=cos(90-theta), cos(theta)=sin(90-theta) and what else also like cot(theta)=tan(90-theta) and tan(theta)=cot(90-theta)
Ez
What’s this called
Take theta = 45
x 2
if say the angle isn't between the two sides?
it's ambiguous in that case
pi/6 + 1/2*i?
hey guys can anyone help me , and explain to me how to solve it , cuz idk
idk lol
bro wth r u saying i dont understand
bruh wut r u talking about 🤔
idk lol what do u mean by b_12_7 lol 😁
its my friends initial , and bd date
lol
lol nice
nice, so its like a special birthday initial
yeah kinda, but were not friends anymore
yk what? idek anything so imma ask chatgpt , ty for helping
bruh
i aint drawing bro
u dont even know my bd , do u ?
i would give up by now they don't even want to know
bro i just dont know what hes talking abt
i just know the c^2=a^2+b^2
so?
ohhh okk
okk tysmm
i understand now
Anyone any doubts?
ty
Do you think I KNOW ! I am DYING out here MAN!!!! 😭
No comment.
Thank you very much.
can U guys help me with 4c
where are you stuck?
4c
i hope you know that the locus of this point P is a circle?
Since the radius is greater than the distance from the origin to the center, the origin lies inside the circle, right?
for maximum value of |z|
This is found by starting at the origin, going to the center, and continuing to the far edge of the circle. that is |z| max= d+r = 5+8=18
with a similar logic you can say that for |z|min you can say r-d=3
i hope you got it? @upper karma
ohhh yh ofc
yh bro i did thx a lot
though not sure about 5 + 8 = 18
whats your doubt ?
the addition 5+8=13 its nothing much
uhh just saying you made a silly with 5 + 8 = 18
ooh sorry, its a typo!
btw how do you know that the maximum the minimum value of z is on the straight line that goes through the origin and the center and where the line intersects the circle
like sure it makes sense when you look at the diagram but yk we just cant assume stuff like that
2 constants in one circle, pi and root two
Or pi*sqrt(8)
Hi, if anyone needs it, I made an extension to a unit circle diagram with tan,cot,sec,csc. I made it primarily for obsidian notes, so that it's easy to read even without zooming in.
Did you draw that circle without a compass?
no, I wish I could do that though
Thanks
Is it true that on Pythagorean triple its; Write odd squares consecutively. Add or subtract 1 to even- numbered semi- squares. Double it arbitrarily by three, four, or five
I don't need help with this I was just messing around
idk this is my homework for school i lowkey couldn't solve it for so long
How do I solve this
What are we solving for?
I have a reasoning above for that
See this
hey so I need help im doing a study guide for similar triangles and need help understanding how to set up and solve problems and maybe find a pattern to use
same lol we got a study group goin on rn in geom & trig 🤔