#geometry-and-trigonometry
1 messages Ā· Page 58 of 1
help i dont know what to do im freaking out šæ
it doesnāt appear to have exactly one solution
Iām having trouble with this problem, Im trying something with a line from A to the perpendicular bisector of CB but it doesnāt seem to be working
I think I have that EFA + BAC = 180
Why exactly
It you draw a horizontal line through F, then its angle with FE and FC are both the same as angle BAC.
How do you know that
Because it's parallel to BEDA.
How do you know that
Because that's what I deined my line to be.
Angle FEA = angle BAC because isosceles triangle.
Angle KFE = angle FEA because parallel lines
Angle KFC = angle BAC becaluse parallel lines.
So angle EFC is two times angle BAC.
And then angle ECF = angle EFC, again because isosceles triangle ...
I thought tangent lines were all the same lenght at intersections
but it has coome to my attention i am critically wrong
I am off about 2 when I multiply 23.2 (One whole triangle side lenght) by 3
You're probably assuming that the three points of tangency are 120° apart on the circle, but that cannot be true.
how do i approach this then
I have 3 points, they are all tangent (Questions states: "If line appears tangent, then they are tangent"
Im going to label the image for easier explanation'
i forgor the C š
I don't know what it is you're computing, but you can find all the side lengths using this:
instead of perpendiculars, label the measure of any angle āxā then start finding all the other angles in terms of x
this is a great problem
i love aops
good job!
Why is it necessarily true that they share an altitude?
from B onto AC
i mean we are considering AX and CX as their bases arent we
Yes
so like
those two come from the same straight line
so of course the altitude dropped from B will be geometrically the same in both cases
not merely equal length but like the segment is one and the same for both
Ok but like, why is that segment the altitude
what's your defn of an altitude of a triangle
it ought to be something equivalent to "a segment from one of the vertices to a point on the straight line containing its opposite side, and perpendicular to said line"
Yeah
yeah os
so*
i think you're overthinking it
we are literally just dropping a perpendicular from the same point (B) onto the same straight line (AC) in both cases
Looks about right
What about the other one though, how have we shown they are the same
How?
Oh wait I see I think
if you drop a perp from B onto the line containing XC, to construct the altitude of triangle BXC, you get BH
if you drop a perp from B onto the line containing AX, to construct the altitude of triangle BAX, you still get BH
it's literally the same one
holy shit they missed some important punctuation in there
- ABCD is a tetrahedron.
- Face BCD is equilateral, with side length 12 units.
- H is the foot of the perpendicular from A onto BCD, and it lies inside the face.
- The area of CDH is 3 times that of BCH.
- The area of DBH is 2 times that of BCH.
- M is the midpoint of side BD.
well i needed to write it out like this to make any sense of it.
cause the run-on sentence going on there is insane
anyway... do you have a diagram of this thing?
i'm not asking if they give one
i am asking whether you have even thought to make one
Oh yes yes
"do you have [thing]" is not, in general, the same question as "does the problem give you [thing]".
I think Ann wants to see your diagram.
^
I do remember that,but drawing it this way make me to visualize it in a easy way
it's actually way easier if you do it my way
that way you actually get a sense of the picture being 3D lol
Okay I will do it from now on
also i don't see H anywhere
H won't be usefully for options C AND D
i would not be so sure
the position of H relative to B, C and D seems relevant!
especially given A is directly above it
i also recommend you make a subdiagram showing only face BCD
Okay
cause the area ratios between CDH, BCH and BDH should be more easily shown on that
Ʀ is an interesting choice of letter for area
anyway i am pretty sure the distances of H to each side can just be computed directly.
knowing BC=CD=DB=12 and these area ratios
Yes
do that
drop the perpendiculars from H onto each side of the triangle
give names to each of the three points that are their bases
and send a photo of the resulting diagram here
mark their lengths as well
ok
CHF are not collinear
ok so you want the distance from A to CM...
and the logical first step to that is to find the distance from H to CM
Okay i will try to
Yay
Got it
The perpendicular distance is 2
2
So now we can use pythogorean theorem
Thanks
solve $cos(3x-15^{\circ}) = \frac{\sqrt{3}}{2} for, 0 \leq x < 180$
did you mean \leq?
uh
I got the reference angle and everything
solve $\cos(3x-15^{\circ})=\frac{\sqrt{3}}{2}$ for $0\leq x\leq 180^{\circ}$
|Annā©
but normally the quadrants are like 90 180 270 and 360 right in a range of 0 to 360
i can't wrap my head around the changed ranges
15
you should explain if you want to answer
cause wolfram can do it for them ofc
maybe you should try solving for all real values of x first
As do cosinverse on the other side it will equal 30 then add 15 which will equal 45 and then divide by 3
Which equals 15
yeah i know that
but i'm trying to know what to do when the range is changed
K
But the way to think of it is:
0 <= 3x <= 540
-15 <= 3x - 15 <= 525
There you go, that's the domain you need to serach for
And x = 15 is only one solution ofc
this gives you only one solution and loses all the rest.
i got x=15, 115, and 135
,calc 3*135-15
Result:
390
keep searching
you're not at the upper limit yet
Let me doublecheck
Ah yes you are
Yeah see what happens when you try to find the next highest solution
Correct btw
all i wanna know is what to do when the range is changed, at school they drew something on the quadrants
@obtuse quiver
imo the best way to do this is to solve for x in R and then filter to your range
instead of trying to memorize a thousand procedures for what to do when the range is in this or that form
how'd i do that
If the range is changed like to 360 then minus the ansr with 360 or with 270 or with 180
According to what the range is
cos(t) = sqrt(3)/2 <=> t = ±pi/3 + 2pi*n, where n ranges over all integers
or in degrees ±60 + 360n
3x - 15 = ±60 + 360n and solve for x as normal
np
all good, thanks ann
btw is this correct $cos\theta = \frac{2}{3} , -180\leq x <180 \newline reference angle=48.1^{\circ} \newline \theta=-131.9,131.9$
uh
,calc cos(48.1 deg)
Result:
0.66783255547105
still getting used to it lol
one sec let me show you this
i drew this quadrant to do that problem
instead of 0 and 360 i put in -180 and 180
because the range was changed
and then -180+48.1 and 180-48.1
idk cos^-1(2/3) comes out as 48.1
wait what
yes but you should have used those values as is, not taken their supplements.
angles are always measured from the positive x axis. the positive x axis is always 0, or an integer multiple of 360.
-180 to 180 still sweeps out a full circle exactly once but it doesn't start on the positive x axis
ah
it starts a half turn across from that
so i should've done this
upside down
is this good
worse
shit
the ±180 are in the right places but the 0 and 90 are both misplaced and unnecessary.
alright so ignoring the 0 and 90
how would i proceed
i have the reference as 48.1
... you would get x = ±48.1 but the whole construction of your diagram makes it nigh impossible to justify that cleanly.
could you tell me how to do it from scratch
if it doesn't take up too much of ur time
afraid it will
ah no problem then
I was following a video online on how to graph cos and sin equations. I was a bit confused why they replaced the 2 in the formula solving for period 2pie/b as 3pie/(1/3) i was thinking because the amplitude is three thatās why but iām still a bit confused if there is like a rule for it
|Annā©
This trigonometry and precalculus video tutorial shows you how to graph trigonometric functions such as sine and cosine functions using transformations, phase shifts, period, and amplitude.
Trigonometry - Basic Introduction: https://www.youtube.com/watch?v=g8VCHoSk5_o
Angle of Elevation Problems:
h...
oh dang
watching on my school account so the comments were turned off
okay thats what i thought thank you!
is the range and domain of a cubic function always infinity unless said otherwise
it's not "infinity"
it's all real numbers.
or (-ā, +ā),
or just R.
but yes.
and the same goes for any polynomial function of odd degree.
if sin(alpha) is equal to -4/5 in quad 4, does this mean that sin(theta) also has the same ratio of -4/5? what is the difference between them, exactly?
... alpha and theta are two different letters which probably denote different angles
thats the difference
you cannot tell anything about sin(Īø) from only the info you wrote here
Any help on the trig question
any advice? i did P = 2 so B = pi, and midpoint = 7+1/2 = 4, and amplitude = 7-1/2 = 2, and since it starts at 0 im assuming its a flipped cos function
!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).
@static hearth sin, cos and tan still denote the same trig functions no matter which letter you write for their input. but if a problem involves two different angles, one of them called α and the other θ, then you obviously have to distinguish between values of trig functions at alpha and those at theta
like idk how to explain it except to repeat the same shit 17000 times
only to have you fire off this fucking GPT shit
this diagram^ is what was confusing me. but now I know that beta, theta, and potentially gamma just represent angles in the context of any given problem.
the problem will tell you all the letters it uses.
they are greek but they are just letters
so yeah
for instance, here I believed that on A) I had to calculate the Beta value in the context of sina = -4/5
but you just go over on the right side and find beta in the context of tanB = 4/1 right?
ew wtf. <@&268886789983436800>
good. itās gone
yes obviously
to find shit for alpha you work with alpha
to find shit for beta you work with beta
so for this, which is just a reference I put on my wall, why would sin(a) = sin(a)cos(B) ?
why wouldnāt sin(a) just equal sin(a)
bahhh nevermind.
I do not see sin(a) = sin(a)cos(B) in your notes
also stuck on this one
Yeah this was wrong it will be just 48.2
can i get an answer and explanation for this problem, I know to take inverse and use inverse of tan but I get -0.174 and 2.967 but mathaway says its wrong
to plug it into your calculator turn cot into 1/tan and solve for tan then use inverse tan on your calculator
and this problem has infinite solutions
Why canāt I understand this? Iām stupid thatās what
Idiot here trying to actually be good at trig, what a fool I am
Well, I check and yeah, itās 5
My apologies, itās just that my math anxiety tends to get the best of me
Grade 11 math hasnāt been that kind to me
Anyway to find another method to get the same result as in ink? (52.23)
Yeah
I tend to worry a lot because I sometimes feel like my teacher does not get that I AM trying to understand, but everything feels so cramped and doesnāt have enough space to breath, I do well in all my other classes, but math annoys me the most
Like the problem above as I do not know HOW anybody could find a second method to the question without the use of a second side for the pythagorean theorem
you can use sin of one angle or cos of the other angle
and you can find the other angle because all the angles add up to 180
oh wait
it probably wants you to do pythagorean theorem
oh
i forgot you just said without pythagorean theorem
lol
theres actually a lot of ways you could do it
also it doesn't say not to use pythagorean theorem...?
The paper was made weirdly
yeah
i bet it wanted you to use pythagorean theorem
Yup and that was supposed to be the Correct Answer BUT, the side didnāt have any other values
But itās okay
I am focusing on other stuff
wdym?
All the stuff from the previous quizzes
I dk why this was graded weirdly
Iām sure I showed all my steps
Isnāt cot literally cos/sin? Therefore making if x/r / y/r
And this is weirder
I tried to solve it as best as I could using the Pythagorean identity
ngl i have no idea what you did
use difference of squares
i think hes supposed to prove it better than that...
maybe not š
i guess they might have just wanted him to multiply it out like (1-sinx)(1+sinx) = 1 - sin^2(x)
but thats not really a proof
i thought it wants him to prove cos^2(x) = 1-sin^2(x) after distributing
but maybe not
yeah, if you can assume that then thats the way
but i don't think you distributed correctly
that might be the problem
But I now know
How to do it
yeh
I just had to times them together
yeah
And then use that identity
yeah
And cross the sinses? Out
but why is difference of squares not a good proof
For the cos^2x
you would use the pythagorean identity
because cos^2(x) = 1 - sin^2(x) is a trig identity, it says "prove the trig identity"
if it wants you to prove cos^2(x) = (1-sin(x))(1+sin(x)) simply because it equals another identity, thats not really a good proof :l
Could someone help me with this? At first I tried using surface area of a sphere using 4pi(r)^2, but it marked it wrong, then i found out if it was half a sphere it would be 2pi(r)^2
Both are wrong?
you need to account for the circle base
is that exactly half a circle?
sphere*
i dont know exactly what a hemisphere is
hemisphere is half a sphere
Did you use the radius or the diameter
?
radius
What do i do with the base?
add an extra pi r^2
huh?
So what should the formula look like
$$3\pi r^2$$
If sphere is 4pi(r)^2
jasoney
what??
because when you cut it in half there is a circle at the bottom
surface area
Then it should be 226.19 2pi (6) ^ 2, 2pi x 36 or 6.283 x 36 = 226.188 or 266.189
Make use of bed as
Bedmas
339.29
Uh could someone confirm? It doesnt let me check no more
If im rounding to nearest hundreths
uh
i got 339.29
how?
3pi(6^2) = (3)(36)pi = 108pi = 339.29
4pir^2 is the surface area of entire circle tho
so 2pir^2 should be half circle...
i missing sum?
I tried using 2pir^2 it was wrong
Can someone explain how i got this wrong? I solved for the radius using the given circumference. I kept the radius in fraction form for better approximation
29.5/(2pi)
V = 4/3pi(29.5/2pi)^3
= 433.53 if rounded to nearest hundreth
@trail tendon
it may be displaying the correct answer after all tries have been attempted
,calc 4/3 * pi * (29.5/(2 * pi))^3
Result:
433.52590365166
Bruh
Apparently volume is 434.19
oh we got it wrong, then
š¤·āāļø
Result:
433.96579644881
They might have done pi = 22/7 instead of 3.14 maybe?
,calc 4/3 * 22/7 * (29.5/(44/7))^3
Result:
433.17712637741
Oh lmao
can someone please help me with this?
its permutation
but idk how to find the favorable outcomes
Well you set aside the two books as said by the question, then you just have to choose 2 out of the 3 books remaining
#discrete-math is a better place for this
Id guess #competition-math would be better but okay
if i set two books aside wont i have 4 left?
Nvm yea
Choose two out of the 4
i used permutation to find total outcomes (360)
prbability = fav outcomes/total outcomes
,calc 654*3
Result:
360
Yea
How many ways can you select 2 from 4?
my teacher said the fav outcomes was 12 in his notes but idk how he got 12 for fav outcomes
Yep
Yep
thanks
Try showing itās a parallelogram; youāre almost there, then use the fact that opposite angles of a parallelogram are congruent
Alternatively, prove two triangles containing those angles are congruent
In a parallelogram, the acute angle is 45 . Find the area of a parallelogram
if its diagonals are 6 cm and 8 cm.
can someone help me with this task please
i dont quite understand it
Do you know the formula A = 1/2 ab sin C for a triangle?
yes
Right then from the picture above, there are 4 smaller triangles
And the centre bisects both diagonals
So we have 2 * (1/2 * 3 * 4 sin 45) + 2 * (1/2 * 3 * 4 sin(180 - 45))
but that gives us approximately 11.27
but the correct answer is 7 as i was told but how do we get 7
Oh wait I misinterpreted the question
So the question must mean that n = 45 right
yes
You could try using coordinate geometry
Then we must have (a + h)^2 + h^2 = 8^2, (a - h)^2 + h^2 = 6^2 if a is the base and h is the height
So (a + h)^2 - (a - h)^2 = 4ah = 28
yes but JEE questions are hell so
Btw, use Approach0 to search for answers to competition problems
Approach Zero: A math-aware search engine.
I will be back after the problem is precalc is done
ok
The first link in Approach0 tells you that tan y = sqrt(2)/2
So options A and C are incorrect
in fact it's B
Yes,the correct answer is B
These are just the mock test questions
The original one's are of a different level
don't bring me more hell lmao
Thr paper comes with solutions but , in most cases they dont make any sense
That is why I ask them here
np
can someone explain how this works and how this is able to rotate a absolute value function
Are you sure that is all the context?
If area of āāthe triangular region AQP is 50
What is the area of āāsquare ABCD
5(PB)=12(PQ)
a and b was easy but for c I tried setting 2sin2x=root2 which gave pi/8 for quadrant 1 (which was correct) I did the same for quad 2 I got 7pi/8 and that wasn't correct The answer key said the answer is x=-pi/8,x=9pi/8, x=3pi/8, and 11pi/8. Can someone explain?
Do you know the formula for 2cos(a)cos(b)?
help
i forgot to study so uh help
i remember first do some triangle?
Then get midpoint of each line?
if you construct a perpendicular bisector of segment AB, then every point on that perpendicular bisector will be same distance from A as is to B
Likewise, if you construct a perpendicular bisector of BC, then every point on that perpendicular bisector will be the same distance from B as is to C
How can you use that to find a point (the boat) which is the same distance away from all three points A, B, and C?
š
Any clues on how to find the measurement of D to G?
Would I have to find the āheightā of the second triangle?
how can I prove that a>b?
maybe you could do it using law of cosines?
good idea, but I'm not sure I can use it already, considering the book didn't prove it yet
hinge theorem
š
I'll search about it, thanks
If you don't have any trigonometry: Drop a perpendicular from A towards BC, meeting it in P, such that the triangles ABP and ACP are right. Then use the fact that BP > PC and Pythagoras.
do i ask geometry questions here instead of in the help section?
Each is accepted, just please don't do both.
I don't know how to do both of the problems
I believe that for the first one it is angles KIR and KER because they are both opposite of the diameter.
for the second one I believe it is FHG and FYG for the same reasons
is it possible to rotate this or no
Somebody help please
What part do you need help with?
Like on how to start. I'm so stuck
Alright so lets do the simple parts first, so when you have a line interesting a line?
They meet at a single point right?
Yes but itās also split into four parts right?
Oh yeah
If youāre thinking of all of those parts as the angles surrounding that one point, theyād all add up to 360
I just failed my trig class. anyone have an online resource/mega test that I can study so that next semester I pass for sure?
Right because of the full rotation
Yup! You can also see it as two half circles
If not sure if Iām correct but the half circle isnāt it 180 degrees
Exactly
:0
If you have one part of that 180, you can subtract that part from 180 to find the other part.
Nice š
Then we also see that the next angle is the same as the one opposite of it. This is always the case
Ones right next to the angle are ones that will ācompleteā the angle making it 180. And the ones opposite of it are just the same as the angle
Yup!
phew
quick question on the 25 degress its called a vertical angle right
so is 40
and 155?
Vertical angles is the rule that says opposite angles are always congruent (the-same)
oh yeah their congruent
in ab?
oh
In geometry its a notation where for example a is parallel to line b just like c||d
so its just saying the parallele line are in the same plane that never intersect
| |
Mhm!
yeah
that why they put it in these line ||
so i tried one on my own and idk if its correct so lemme send it
cause 130+50=180
Yup perfect!
Yay š
Iāve only done these two so far
This one Cuase itās the same thing like the first one
So I have measures 1 and 3
and 2 because I noticed 1 and 2 are the same degree 130
Mhm and why is that?
Yes, but not quite. Itās because the two lines intersecting that line are parallel
ooh
If they werenāt parallel or if not stated they are, you canāt assume that.
i see
Yup!
oh so thats what i saw
The 130 to the 130 & 50 to the 50 are corresponding angles
thats pretty simples
So what would be the relationship between 1 & 5
Corresponding?
Exactly
o
What about 1 to 8
supplementary
yeah ss exterior is supplementary aswell
Exactly, which means they are supplementy
lets go
What about 4 to 5
Which means the angles are?
congruent
Nice
thank god i thought it was supplementary for a second
You should be able to complete your assignment pretty easily with that
Mhm
š
This was actually easy šØ
Now I just hope I didnāt mess up
sorry for bad lighting and quality and messy hand writing š
You got it good job!
Yessss Thank you for you help!!! I just needed a refresher ā¤ļø
Ofc ofc!
I really feel stupid right now
I can't figure out how to do (sin(x)+cos(x)) ^2
In my brain I think it'll be sin^2(x) + 2sin(x)cos(x) + cos^2(x) but then a math app tells me the answer is sin(2x) + 1
those are the same things
sin^2(x) + cos^2(x) = 1
and
2sinxcosx = sin2x
I think I am lost, why are those the same
I'm in the process of learning them but this is my first day so far
Oohh.. so for Pythagorean identities I can add the sin^2 + cos^2 to equal 1, but 2sin(x)cos(x) still confuses me
Nevermind I found it, I forgot about double angle identities
How would I get x without cancelling it both
how so?
dumb example: if x were equal to 2, then
(x+8)^2 would be (2+8)^2 = 10^2 = 100
but x^2 + 64 would be 2^2 + 64 = 4 + 64 = 68
either recall how to expand (a+b)^2, or expand (x+8)(x+8) the long way.
yes of course
in general (a+b)^n is not equal to a^n+b^n. powers don't distribute over addition like that.
so what should i do now
how would you solve the equation
x^2 + 256 = x^2 + 16x + 64
if it was given to you like that to begin with?
what first step would you take
Get the Xās by themselves?
square root the x
the question was not addressed to you.
or minus the 256 on both sides
Sorry
if you mean to square root both sides, that's supremely unhelpful.
why not just subtract x^2 from both sides?
that seems right when i plug it in in the reg pythagoreon theorem equation, tysm
yup there you have it
@dark sparrow do yk how to do my problem ive been stuck on it for a while plz
i am not going to even touch it
there are people on this server who know how to do this, yes.
@upper karma what is troubling you here?
I don't know where to start
ok so you have a circular sheet of metal and you are cutting a hexagon out of it.
everything inside the circle but outside the hexagon is the scraps that they ask you about.
do you understand this? y/n
(i am not done yet, but i am bringing you up to the same page as myself)
@upper karma
yes
ok
so the scrap area equals the area of the circle minus the area of the hexagon.
do you see how to continue?
If I am prompted cot = 2/3 and sinx > 0 and then asked
sin2x
Would my answer using the double angle identity be
sin2x = ~1.2569
or
sin2x = 12/13
I can't remember if I replace sin(x)cos(x) with that or if I compute it. Forgive me I have been working for 15 hrs straight and I am tired
how did you get 1.2569
also go take a fucking nap for gods sake
15 hours straight is like a million times longer than you should be working
I have a quiz due in 2 hours that I haven't had time to study for š
2sin(3/sqrt13)cos(2/sqrt13)
people should only be working like 5 seconds per work time š
you got yourself royally confused.
š
I have lost the barrier between knowing what tf radians and degree mode does atm
in this instance my use of "million" is not to be taken literally, but also 1/1,000,000 of 15 hours is less than that.
oh yeah its less than one second
Was I right to still compute the sin and cos but meant to do this in degree mode?
it actually doesn't matter what mode you use bc this is a non calculator question
I.. am even more cdonfused now, let me just take a picture of the question
From my fading mental capacity only thing I could deduce is to use double angle identity
give me a couple minutes to clock in to work
Sure, I'll just write what I did rq
What I did was
find hypot = sqrt13
sin2x = 2sin(3/sqrt13)cos(2/sqrt13) = ~1.2569
or
sin2x = 2(3/sqrt13)(2/sqrt13) = 12/13
I finally discovered I was dumb and not meant to compute it, the 2nd option was right (Dear God I hope)
yes, it is.
it's sin(x) = 3/sqrt(13), not the sine of 3/sqrt(13)
It only gets worse from here 
95% of it getting worse is because you have overworked yourself
Oh 100% but if I don't I get a lovely zero
All I have left is another of these but with half angle and then a power reduction and something I don't even know
Could someone quickly confirm for me if the U in half angle identities for.. say sin(u/2) is equal to y/c?
What are y and c?
opposite = y and hypotenuse = c
Yes, this is correct
Oh okay great, ty
U is just a name for the angle, you can use whatever letter you like
ah okay
Ok I am swinging back full circle, if I don't have radians to easily get cosu do I replace cosu with -4/5 if my opposite is -4 and hypot is 5?
to make it
+- sqrt( 1-(-4/5) / 2 )
Coincidentally my teachers lecture has the exact same problem on the quiz, so nvm I can figure this out
cos ec typesetting fail 
?
they tried to type cosec as in cosecant, but whatever software they used for typesetting took the first three letters as meaning cos
Oh
it is an inconsequential but noticeable typesetting defect
csc anyway...
(i don't know how to do this problem without headache)
This is what the solution says(Screen shot was not allowed so I had to write it down)
you mean 2^(r-1) and not 2^(n-1) in the sum?
Something to remember or can it be derived in a easy way ?
mb
Okay
Surely you just induct or sth
,rotate
That works, ty
keep going
expand this
you will get a cos^2(2x)
apply that identity again

Is the answer
3 + 3cos(2x)
/
4
never write fractions like this again.
but also definitely not.
show your work so i can tell you where you screwed up.
oh okay so the 2 * goes inside the cos not on the outside of the parenthesis
..... yes obviously since you are working with cos^2(2x) and not with 2cos^2(x)...
So right after I convert cos^2(2x) it should look like
( 1 + 2cos(2x) + ((1 + cos(4x)/2) ) / 4
```?
Any idea, Ann ?
yes, and now clean that up
no
For the first time
it's more like i don't want to touch that problem.
Oh
It's all for naught, I can't finish all these questions in time š¦
Wait I don't get what the question wants you to do
You can write cos^4 x in terms of a constant, cos 2x, and cos 4x
that is exactly what it wants you do i guess
@obsidian harness
which one?
Both
I CAN SLEEEPPP I submitted it a whopping 4 minutes before I would have gotten 0 points. Fuck college
South?
cba
Cba?
can't be assed
pls ask in #calculus
or in one of the help channels, see #āhow-to-get-help to know where to find them
#precalculus but honestly just go wherever in pre-uni.
Okay thank you
!da2a
No need to ask āCan I askā¦?ā or āDoes anyone know aboutā¦?āāitās faster for everyone if you just ask your question! See https://dontasktoask.com/
whatās the question
so uh
triangle with A 38degrees, B 55degrees, C 87degrees and a 14m, c and b are unknown and they want me to find out what c is
oh i already got proofs down i meant like
well i would love some help understanding it
but
this
sorry for crude drawings
this one š
there is nothing particularly deep going on here
just plug into law of sines and solve for c
a/sin(A)=b/sin(B)=c/sin(C)
Nvm sorry oops
can someone give me the step by step process of solving for the surface area of this figure? Im stumped and I have gotten like 5 different answers
(I just need the process, I know that this answer here is correct because I checked the answer key to the assignment)
can you show your most recent attempt
I erased it
I just need to know how to use the formula
because I currently have no idea how to plug the numbers in
area of each face (there are 5)
doable with basic area of rectangles and triangles
then add them all up
the 30in side length you calculated is correct btw
do you have like the actual formula im supposed to use for a polyhedron
and do you know how I would plug it in for this particular scenario
general formula would be
add up area of each face/surface
ok
there are formulae for certain solids,
but that's where they come from, so better off remembering that instead
instead of a different formula for each one
yeah its weird because our instructor had us remember a specific formula for a polyhedron and it makes little sense
priority is to remember where stuff comes from
if you rely fully on memorising formula and don't know where they come from
and you for some reason forget or misremember, you're screwed
I wish this is how we did it
unfortunately public education thinks that everything is needed to be memorized
Heyy
Can somebody help me derive the formula for the excenter of a triangle?
I know it would require me to use external angle bisector theorem but I can't figure out how can I do that?
can someone help me with geometry and solving for volume
Given the positions of the Moon, Alice, and Bob, find the length of the shortest path that starts at one of the players, touches (or crosses) the edge or the interior of the Moon, and ends at the position of the other player.
Can someone explain this to me someone told me the answer was 80 but I need to understand how itās 80
assuming that dot is the center...
oh Thank you for the help know I understand it
ok so basically angle F is a right angle because the diameter is the hypotenuse, and the measure of the arc is twice the measure angle GFP, which means it is 80 degrees
Let MA and MB be tangents to (O). MCD is the secant line. Draw BK and BL perpendicular to AC and AD at K and L respectively. KL intersects CD at I. Prove that: IK = IL
can someone help me?
Can somebody help?
I'm really stuck on this for 2 days.
for the 4 square root of 2, is it just asking for the square root of 2 multiplied by 4?
wdym by that
the top left thing
wut abt it
it means 4 multiply wit sqrt2
it's not asking for that as such.
but $4\sqrt{2}$ does \textit{mean} $4 \times \sqrt{2}$, yes.
|Annā©
wait
so
2 legs on a 45 45 triangle are 4 root 2
and A^2 + B^2 = C^2
so 4 root 2 squared+ 4 root 2 squared would equal c^2
but the ^2 cancels out the root
so its 4X2+4X2= C^2
which means c^2 equals 16
but its not
the hypontenuse is 8
so why is it 8
This is not correct
Also donāt use x as a multiplication symbol
use *
alr
or \* to stop discord eating it as italics
*
also use sqrt() for square root
k
also $(4 \sqrt{2})^2 \neq 4 \cdot 2$.
|Annā©
how come
$(a \cdot b)^2 \neq a \cdot (b^2)$.
|Annā©
Is somebody here actually available now?
Please refer to my question above
This one
someone help my boy
Not gonna lie
I thought I'd get help here
But I have been ignored for more than 24 hrs straight
No one owes you their time
Yeah they don't of course
I just said I thought someone would help me
Sorry if it sounded rude
Also thatās a fairly non trivial question so the number of people willing and able to help is lower than some other questions
Iād recommend going to a dedicated help channel, those are normally easier to get help in from my experience
Can you send some links?
I don't really know any
Even this channel was recommended to me by a friend of mine
not only is it a nontrivial question
it's also very unclear as stated
you didn't tell us what data you are given about your triangle and what output you expect (coordinates of the excenter, maybe?)
Yes I need the coordinates of the excenter
The given can be summed up in this figure
I've posted the same in the help section though
Do you have any idea though? @dark sparrow
i don't really care about this enough to work anything out, so no.
ppl on here either aren't that good at that kind of geometry or don't care, apparently lol
Whatever man
If I get something on the help section, well nice
If I get something here, well that's nice too
If I don't, I'll eventually figure out by myself after sometime
for the record im more of the first one š
that doesn't look like "new to geometry" š
like i aint even know what an excenter is
the center of a circle tangent to one side and the extensions of the other two.
Maybe man
I'm an Asian
And you know how it is here š
That is kinda the consequence of what it primarily is
when i think of geometry i think of like basic finding degrees and arc lengths of circles n stuff
the hard part is like all the weird things liek excenter
??
what is tangent, to one side of what, and the extensions of the other two what
is this a triangle?
It's the intersection point of the internal angle bisector of one of the angles and the external angle bisectors of the other 2
that's your definition of it?
you don't know what the word "tangent" means? as in a line tangent to a circle?
but yes excircles and excenters are defined for a triangle
That's the definition on wiki, that's what I was told by my teacher
i thought you were saying the center was tangent to the circle, i don't understand english š
what is your native language
... what other languages do you speak
i would say the only language im fluent at is english
i speak a little spanish ig
the center of a circle, tangent to one side
to me, another way of saying this
the center of a circle is tangent to one side
the center of a circle is a noun, tangent to one side is i guess an adjective phrase of some sort? idk grammar but the sentence doesnt make sense to me
;-;
the center of [a circle which is tangent to [one side and the extensions of the other two]]
apologies for not making my sentences unmisinterpretable
After thinking a lot, I've reached the result
It's really satisfying at the end. Not gonna lie
how am i supposed to tell when im supposed to use the angle i get and when im supposed to subtract it from 180
how exactly did you get these angles?
cause the sine one is easier
easier to make mistakes with the cosine one
with the sine law you run into the issue that sin(180°-x) = sin(x),
so you have to know if the angle you're calculating is acute or obtuse
since sin^-1 will only ever give you the acute ones
oh
and that, if you so desire, can be accomplished by comparing a^2 + b^2 with c^2 (where a and b are the sides adjacent to the angle in question and c is the 3rd side)
if a^2+b^2 were equal to c^2 the angle would obviously be right, bc pythagoras
if a^2 + b^2 < c^2 the angle is obtuse, and if a^2 + b^2 > c^2 the angle is acute.
very wrong photo.
what the skibidi
but then again, this is about as difficult as just applying the cosine law to begin with.
since cosine law would have you calculate (a^2 + b^2 - c^2)/(2ab) anyway.
so long story short, use the cosine rule if i have 3 sides unless i can clearly tell if the angles are obtuse or acute at least
nothing wrong with just always using the cosine rule if you have 3 sides.
though.