#geometry-and-trigonometry

1 messages · Page 93 of 1

lost lotus
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?

dark sparrow
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how much linalg do you know

lost lotus
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yes

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a bit

dark sparrow
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would you be able to find the eigenvalues and eigenvectors of a matrix if asked

lost lotus
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no

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i changed subjects and stoped tensors at grade 7

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started tesnor at last 3 months of grade 6

dark sparrow
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maybe learn linear algebra properly if you are so inclined

lost lotus
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ok

lapis moon
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,tikz
\pgfmathsetmacro\myR{sqrt(0.5)}
\draw (0,0) circle (1);
\draw (1,0) circle (\myR);
\foreach \t in {90,180,270} {
\draw[dashed, gray] (\t:1) circle (\myR);
}
\path[pattern color=red!60, pattern=north east lines] (0.75,{-sqrt(7)/4}) arc ({-atan(sqrt(7)/3)}:{atan(sqrt(7)/3)}:1) -- cycle;
\path[pattern color=blue!60, pattern=north west lines] (0.75,{sqrt(7)/4}) arc ({180-atan(sqrt(7))}:{180+atan(sqrt(7))}:{sqrt(0.5)}) -- cycle;

somber coyoteBOT
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vin100

lapis moon
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those shaded areas can now be calculated (in terns of one unknown)

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the rest is just algebra

cursive bolt
lapis moon
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@uneven scarab for your question in #help-49 message, you have to show your work
you can start with letting some quantity with a variable, then use it to find it's relation between other quantities

\begin{tikzpicture}
\foreach[count=\j from 0] \i in {1,...,6}{
  \tkzDefPoint(\j*60:3){A_\i}
  \tkzDrawPoint(A_\i)
}
\tkzDrawPolygon(A_1,A_...,A_6)
\tkzDrawSegments[blue, dim={\(s\), 20pt,}](A_1,A_6 A_6,A_5 A_5,A_4 A_4,A_3 A_3,A_2 A_2,A_1)
% mid point of base
\tkzDefMidPoint(A_5,A_6) \tkzGetPoint{M}
\tkzDrawPoint(M)
% draw triangle
\tkzDrawPolygon[thick, blue](A_2,A_3,M)
% draw given circle
\tkzDefCircle[circum](A_2,A_3,M) \tkzGetPoint{O}
\tkzDrawPoint(O)
\tkzDrawCircle[radius, purple, thick](O,M)
\tkzDrawSegments[red, dim={\(R\), 10pt,}](A_2,O O,M O,A_3)
\tkzLabelPoints(A_1,A_...,A_6,M,O)
\end{tikzpicture}
somber coyoteBOT
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vin100

lapis moon
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@obsidian harness i think you can actually "do cogeom" while "pretending to do geom"
by drawing auxiliary vertical and horizontal lines

empty yew
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can we tell xy=0 the coordinate axes?

sudden solstice
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Can someone help me understand it please I think I got them all wrong and I am using this as my “rule” sheet

empty yew
sudden solstice
sullen maple
sudden solstice
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Yes by either AA SSS SAS

empty yew
empty yew
# sudden solstice Prove

watch first five minutes if you're new to congruency in triangles:https://youtu.be/VXlFEilh-cw?si=NGiXUEEg3qGM6d7g

This geometry video tutorial provides a basic introduction into triangle similarity. it explains how to use two column proofs in order to prove if two triangles are similar using the mostly the AA postulates. Other triangle similarity postulates mentioned are the AAA, SSS, and SAS postulates. Theorems used in this video include the base angle...

▶ Play video
wanton sinew
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Hi, absolute beginner here, could someone explain this to me pleasee.

empty yew
wanton sinew
empty yew
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it is based on similarity of triangles

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Since triangle ACB is similar to triangle AED we have that ratio

wanton sinew
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I see, so a fraction with two corresponding sides as the numerator and denominator is equal to an other fraction with different corresponding sides?

empty yew
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when two triangles are similar like triangle PQR is similar to triangle EDF we have the above ratio

empty yew
wanton sinew
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understood! thanks a ton!

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one more thing, is there perhaps a name for this concept so I can refer to online resources?

empty yew
dark sparrow
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an angle where you care about if it's clockwise or counterclockwise?

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@echo sigil are you stuck on a specific question here

rapid hearth
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i need help quickkkk

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am i correct

silent plank
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show your work

echo sigil
dark sparrow
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huh...

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hm

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ok that's not something i can speak about with confidence sorry

lapis moon
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it's like

#

,tikz
\draw[->, blue] (0,0) -- (-5, 0) node [midway, below] {$\vec{a}$};
\draw[->, red] (-5, 0.5) -- (3, 0.5) node [midway, above] {$\vec{b}$};
\draw[->, thick, green!50!black] (0,0) -- (3, 0) node [midway, below] {$\vec{a} + \vec{b}$};

somber coyoteBOT
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vin100

lapis moon
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BHS = ∡(B̅H̅, H̅S̅) = ∡(B̅H̅, P̅H̅) + ∡(P̅H̅, H̅S̅)
= ∡BHP + ∡PHS

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just like

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,,\overrightarrow{AC} = \overrightarrow{AB} + \overrightarrow{BC}

somber coyoteBOT
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vin100

lapis moon
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the "element" surrounding the '+' is the same

echo sigil
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So as I understand BHS = PHS + BHP since BHP has a different direction than other two so basically it is BHS = PHS -BHP?

lapis moon
lapis moon
# somber coyote **vin100**

left (blue) vector has a different "sense" than the other two vectors, but
green (thick) vector is still the vector sum of the other two vectors
https://math.stackexchange.com/q/339142/290189

echo sigil
lapis moon
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Your choice of notation isn't goid

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good*

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hindering you to see the truth

stuck nest
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Help at hard circle question

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Somebody help pls..

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Help-35

timber copper
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help me (number 4, not I've already solved it)

chrome token
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can someone tell me if its a nice qn
Prove or disprove
Given that r satisfies
Pr - pi r^2 = A
and we have a convex polygon of perimeter P and area A, we can inscribe a circle of radius atleast r.

empty yew
uneven scarab
twin robin
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evett :DDDD

tepid oyster
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why can’t i turn the two negs into pos ?

trail tendon
tepid oyster
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ok that makes sense

empty yew
left wren
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Yall im failing geom i just got a 67 out 200 on my quarter test. Im so screwed pls i rly need someone to tutor or help me broo

maiden brook
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like specifically

left wren
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It was on like sine cosin basic geom stuff, similarity figures and special right triangles

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It was 134 out of 200

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My teacher graded it wrong 😭💀

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But now we are learning circumference, area of circles, sectors, test in a few days and i have no idea how to do it

silent plank
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might be hard to find a dedicated tutor, but you're free to post questions you're struggling with
ideally in a personal channel #❓how-to-get-help

real vine
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$$cosA-sinA=\sqrt[2]{2}*cos(A+pi/4)$$.How can you get this result using sin A-sinB ?

somber coyoteBOT
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wolly5114

dark sparrow
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ok just to fix your LaTeX

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$\cos(A) - \sin(A) = \sqrt{2} \cdot \cos \left( A + \frac{\pi}{4} \right)$

somber coyoteBOT
dark sparrow
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but anyway, $\cos(A) = \sin\paren{\frac{\pi}{2} - A}$.

somber coyoteBOT
cerulean axle
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hello

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why does arcsin of sin of x equal x?

silent plank
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that isn't always true

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its only true for x in [-pi/2, pi/2]
because that's how the inverse is defined

cerulean axle
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ahh, okay

real vine
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@dark sparrow but how does $$\frac{\sqrt[2]{2}}{2}*cos(\frac{x}{2})-\frac{\sqrt[2]{2}}{2}sin(\frac{x}{2}$$ = $$cos((\frac{x}{2})+pi/4))$$

dark sparrow
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badtex

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you should not put the equals sign outside of dollars

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also your equality is incorrect anyway

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also is there a reason why you insist on explicitly writing $\sqrt[2]{2}$ instead of $\sqrt{2}$?

somber coyoteBOT
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wolly5114

dark sparrow
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ok your tex is still bad in many ways but now at least your equality is correct

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and it follows from the angle sum formula for cos(x+y).

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$$\frac{\sqrt{2}}{2} \cos \left(\frac{x}{2}\right) - \frac{\sqrt{2}}{2} \sin \left(\frac{x}{2}\right) = \cos \left(\frac{x}{2} + \frac{\pi}{4}\right)$$
somber coyoteBOT
dark sparrow
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this is what you meant to write, yes?

real vine
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where does cos(x+y) come from in my equation?

real vine
dark sparrow
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cos(x/2 + pi/4)

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apply cos(x+y) = cos(x)cos(y) - sin(x)sin(y) with x/2 for your x and pi/4 for your y

real vine
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you can't use the terms from the left to prove the right cos angle?

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I've used ChatGPT but it doesn't explain how all that left equals the right side

dark sparrow
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!nogpt

lime crownBOT
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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).

dark sparrow
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are you asking like... is it possible to somehow go specifically from the left to the right somehow, rather than the reverse?

real vine
dark sparrow
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ok hold on

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maybe we are getting off track somehow.

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can we reset all the way to your original problem?

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what do you really want to prove, and by what means?

real vine
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Did it used arcsine?

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I know that $$sinA-sinB=2sin(\frac{A-B}{2})*cos(\frac{A+B}{2})$$

somber coyoteBOT
#

wolly5114

dark sparrow
real vine
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$\cos \left(\frac{x}{2} + \frac{\pi}{4}\right)$ Do you just expand this cos expression? That's what I'm asking How did that cos appeared from

somber coyoteBOT
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wolly5114

dark sparrow
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ugh.

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ok

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wait

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please

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can you send the ORIGINAL problem EXACTLY as you encountered it. PLEASE.

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im not going to ask for this a second time.

real vine
dark sparrow
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so your original question is $\lim_{x \to \pi/4} \frac{\cos(x/2) - \sin(x/2)}{4x^2 - \pi^2}$

somber coyoteBOT
dark sparrow
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yes?

real vine
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well it was a difference of sines and ChatGPT showed me that answer

dark sparrow
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ok sorry i have to go now i cannot continue this.

real vine
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I have no idea how that cos appeared from

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also x tends to pi/2 and not pi/4

stuck nest
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can someone help me too

empty yew
lime crownBOT
stuck nest
cold pumice
craggy orbit
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Prove that sin^2 a + cos^2 a = 1.

austere silo
upper karma
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Meow

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prove sin (120) =-1/2

empty yew
obsidian harness
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and that's actually incorrect; the corresponding principal angle will be 180 - 120 = 60 deg

empty yew
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,w sin(120 deg)

somber coyoteBOT
obsidian harness
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,w sin(120 rad)

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just for good measure

empty yew
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is he asking for radian?

silent plank
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equation is false regardless

obsidian harness
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yeah in the off chance it was suspiciously close to -1/2

upper karma
craggy orbit
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,w sin(120 deg)

silent plank
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what are you allowed to use?

grand path
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hello , i'm here cuz i have a math problem that i don't really know how to resolve. her's the question:

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on a board made of 9 by 2 squares , we put coins on the square such that all squares either have a coin on them or share a side with square that has a coin on it. what is the minimum number of coins needed?

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so i have an idea of the solution, which is five

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but i just don't really know if that's the best solution , and i wanna know if it's possible to prove that this is the best solution

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i thought of using some kind of graph but i also don't know how to use them

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so if anybody got any idea on how to prove this is the best configuration of coins or on how to start , i would gladly appreciate it;

grand path
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Did i post on the wrong channel?

trail tendon
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probably not, i agree with you that it looks correct but i don't know how to prove it either lol

grand path
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My teacher has the correction, i'll ask her for it tomorrow

maiden brook
grand path
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A math calender

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French one

maiden brook
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how does that have to do with a calendar

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but yes 5 is the minimum

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there are multiple ways of seeing this just think about it for a minute

grand path
grand path
maiden brook
grand path
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Well that's the thing, i don't have ideas.
I thought about a graph where the vertex would be the suares and the edges woukd link which square share a side with which, but that doesn't give me any ideas on how to continue

maiden brook
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I definitely don’t think u need a graph (there could be a solution involving that), I am not very well versed with graphs

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did your teacher say u needed a solution involving a graph?

wet pond
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made a silly triangle

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for anybody who wants a triangle

grand path
maiden brook
grand path
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Cuz that's what i'm currently learning in my free time and thought that it could work

maiden brook
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yeah thats pretty unrelated i think

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so to start off what r u trying to prove?

grand path
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That the solution of five is the most optimal solutiob

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I have to sleep

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Gn

maiden brook
grand path
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That the solution found is the most optimal?

maiden brook
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yeah

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I mean to start off your solution does work

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can u use just 1 coin?

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do u know the equation for a circle?

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!nosols

lime crownBOT
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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.

maiden brook
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what just happened to that guy

grand path
grand path
maiden brook
grand path
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Oh okay

grand path
maiden brook
grand path
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For a proof, it could be something about counting the number of squares between coins, and since to maximize the effect of one coin, you need to have no overlap. So you have to have 2 spaces between coins

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(At least horizobtally, vertically is smth else)

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Wait no

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That doesn't work

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Wait ik

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I can show that to minimize the number of coins, k need the maximize the effect of a coin so that a square only shares one side with a coined square.

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Then i can start at the extremities and show that the best way to put another coin is to put it the way the drawing show

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Since there really is two solution with no overlap(the drawing and the drawing ritated 180 drawings. But both have 5 coins)

granite marsh
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?????????

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what's happening guyzzz?

grand path
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I can have 6 cases.
The cases are:
the coin is on a upper extremity ,
the coin is on a lower extremity.

The coin is an uneven number of square from the side of the board and is on a upper square.
The coin is an uneven number of square from the side of the board and is on a upper square.

The coin is an even number of square from the side of the board and is on a upper square.
The coin is an even number of square from the side of the board and is on a upper square.

grand path
granite marsh
#

oh

grand path
maiden brook
grand path
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Well on the current board, 3 if on an extremity and 4 on the rest?

maiden brook
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yeah

grand path
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I'm sorry but i don't understand

maiden brook
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think about it

grand path
maiden brook
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what other information do u know about the number of squares

grand path
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There are 18 of them

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Oh

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Yeah i understand

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The ony way to divide 18 into addition of 4 and 3 is 3×4+2×3

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And 3+2 = 5

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Well technically there's 3× 6 but the number of coins is bigger so the answer is the previous one

maiden brook
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good

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Or just that four multiples of three or four is too few squares

upper karma
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is this right

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well i should have named that (0,0) and (1,0) instead of 0 and 1

chrome token
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given a unit circle, consider a convex polygon which contains the unit circle, given the area of the polygon is A, what is the maximum perimeter of said polygon?

wise shoal
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ughh i just started geometry

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i am SO NOT built for this

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i miss quadratics

empty yew
upper karma
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#help-28 someone help me with my geo 😭

upper karma
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Help

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I think I'm inputting this into the calc wrong

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?

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Ion use steam

paper spear
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trangle😻😻😻📐📐📐📐📐

high vault
stuck nest
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Geometry>calculus

granite marsh
stuck nest
frozen ocean
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noone likes geometry

graceful talon
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i like geometry

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it's my first math love

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doesn't mean I'm good at it tho

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u can see calculus in the lens of geometry

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so saying geometry > calculus is …

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shows a narrow view of both subjects . i just have to say something u can safely ignore this part

signal vapor
thorny pawn
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I like it

signal vapor
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||coordinate geometry||

thorny pawn
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Just a lot of content

gleaming pebble
#

do you know any angles of triangle ABC

frozen helm
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Did you got the value Y

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?

gleaming pebble
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yeah so which angle does that give you

frozen helm
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Product of gradients of l1 and l2 will be -1

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If they are perpendicular

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Using the point intercept for of the gradient find k

gleaming pebble
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you're overcomplicating it

frozen helm
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Make the equations of lines and equate them for the intersection point

gleaming pebble
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hm i disagree

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they intersect at point C, right?

frozen helm
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Well have you done the solution can you show ?

floral flare
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hi is this the channel for asking questions?

gleaming pebble
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so if they're perpendicular

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which angle would be 90 degrees

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yeah lines L1 and L2 are perpendicular

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do you have a diagram?

frozen helm
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All the angles would be 90 degrees

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They would make a perfect cross

gleaming pebble
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i can make a diagram if that would help

frozen helm
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Please I

gleaming pebble
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hm, this is not quite right

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does this make sense?

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uh i don't know what you mean by y coordinate of a line

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let's go back to trying to find the angles of triangle ABC

frozen helm
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You can’t

gleaming pebble
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we're given that L1 and L2 are perpendicular, so which angle is 90 degrees

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yes

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and what else are we given about triangle ABC

frozen helm
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Only one angle is given

gleaming pebble
frozen helm
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Wait then the other two angles would be 45 each .

gleaming pebble
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yes

frozen helm
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Well anyway we still need k

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To solve using any property of triangle

gleaming pebble
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part (b) just asks for the slope of L1

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so if L1 forms a 45 degree angle with a vertical line

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what is its slope?

frozen helm
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How ?

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Oh got it

frozen helm
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Slope of any line is tan ( a) where a is smallest angle the line makes with the horizontal

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But in our case it’s 45 🙌

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No

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AC perpendicular to BC

frozen helm
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But this can’t be true as the gradient for AC is less than zero but with this it is one

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Try to use distance formula on both the sides of triangle

gleaming pebble
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no don't use distance formula

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if you have a vertical line

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and another line at a 45 degree angle

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what is the slope of the red line

stuck nest
frozen ocean
upper karma
#

guys why are those two angles same

cunning lion
#

blue angle a is equal to 43 degrees due to opposite angles, which means purple angle B is equal to 90 - 43, which means the bottom left angle is equal to 90 - (90 - 43) = 43

terse skiff
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Anyone knows about geometric proof

upper karma
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yes as shown by cloud i was able to make sense of that

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well i don't really have to do the proof of it

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its part of physics problems

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and u just use it

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xd

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but proving it is pretty trivial too ngl

terse skiff
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Im talking about another geometry unit

upper karma
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i have done it before

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oh

terse skiff
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It’s where they give you a statement, which is the angle size and stuff like that and you have to find the proof which either given or bisector or reflexive property

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Sometimes they let you find the statement, but they give you the proof

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If you know what I’m talking about

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For example: if AD = AD that’s the statement and the reason of it is reflexive property

vernal valley
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hello

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this one

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it doesnt have to be trig function

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just whatever u think is easiest

thorny cobalt
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Looks like e^x or something

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Some exponential

vernal valley
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it touches 16,0 and 20,3

vernal valley
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dang we thought really differently

thorny cobalt
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Or it’s a very restricted

vernal valley
thorny cobalt
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Trig function

vernal valley
vernal valley
thorny cobalt
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That’s what your assignment is to do here?

vernal valley
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that touches those two and looks similar to that

vernal valley
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we have to model stuff

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and show how we did it and why we did it

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then translate/transform it bla bla bla units to the right

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or reflect it

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and they say theres many possible answers so the thing they looking for is what our thinking and assumptions was

thorny cobalt
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Well it looks like an inflection point, so it would likely have to be a trig function that is being multiplied by like 6 or something if 3 is the half way

vernal valley
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dang bruh

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😭

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i thought of it as a parabola

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and just used 16,0 as a vertex

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then used a domain to restrict it a bunch

vernal valley
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that is one correct answer

thorny cobalt
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I mean I guess it could be, it’s just not really a lot of information haha, you can make many functions look the exact same if you restrict its domain

vernal valley
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for us to show that we can use any function

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because they just threw like 6 at us in like 3 weeks

thorny cobalt
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Very odd test

vernal valley
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the only one i knew before this was parabola

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😭

vernal valley
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and then for like higher mark we have to generalise the equation

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like put in values like m and n which make the function move up/down left/right

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well atleast after this ill learn something ive never learnt but only heard of before

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calculusss

thorny cobalt
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Uh

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This is not calculus lol

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Im trying to think of other ones

vernal valley
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after the whole unit

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of this

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we will learn it next term/semester whatever u call it

vernal valley
thorny cobalt
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No matter how I’ve deformed it thus far it is not really similar

vernal valley
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😭

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yea ion think its possible with a trig function

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my teacher used a cubic

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everyone in my class just did parabola or cubic tbh

thorny cobalt
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Sorta

vernal valley
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i think that hit 20,3

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idk how u can make it do 16,0 tho

thorny cobalt
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Yeah I’d just stick to simpler ones parabola is good, maybe try hyperbola or something

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x^2 - y^2

vernal valley
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oh

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i never heard of one

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ig imma learn that one too

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well i heard of it once somewhere but idk what it is

thorny cobalt
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Yeah good luck man that’s a rly weird assignment I’ve never done anything like that, sounds confusing especially at your math level

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Like if I were you I’d be so confused lol

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I had it easy and I was confused

vernal valley
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😭

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thanks anyway

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have a good one

thorny cobalt
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You too !

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Oh yeah one last thing

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Don’t ask it for the answers I never advise doing so

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But the AI chat bots are pretty decent at explaining complicated topics very simply

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Again, seriously don’t have it do your work, but great tutor

dark sparrow
topaz sluice
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Guys pls help me part c) of this problem

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This is an illustration of this problem.

restive flare
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You can easily solve part a)

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by using simple circle theorems

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oops ill try and do part c

topaz sluice
topaz sluice
restive flare
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yeah, i can have a look at part c in a bit

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but on the surface, at first i was thinking of pascals theorem?

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but thats only a guess

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ill get pen and paper and try it later

restive flare
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yeah i couldnt think of a use of that either

topaz sluice
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Can you see F is orthocenter of APQ ?

restive flare
#

Can you prove it?

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I only see one right angle

topaz sluice
restive flare
#

but it does look like it tho

topaz sluice
restive flare
#

how do you know PT is an altitude tho

topaz sluice
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AI is perpendicular to PQ

restive flare
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but how about PT?

topaz sluice
restive flare
#

Oh wait

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triangle PTQ is an enclosed trianlge in a semicircle

#

so angle PTQ has to be 90

topaz sluice
#

PTQ is an inscribed angle that intercepts a semicircle (O) so PTQ = 90', can you see that PQ is the diameter of circle (O)?

topaz sluice
#

Like that

restive flare
#

yeah then we make sense

#

yeah then it shows the altitudes, orthocenter so triangle PAQ is in fact a triangle so PTA are on a straight line

#

blah blah blah

topaz sluice
#

It is not true

restive flare
#

why?

topaz sluice
#

We just prove that PT is perpendicular to QT

#

What about AT ?

topaz sluice
#

@restive flare

restive flare
#

yeah im working on it

topaz sluice
#

It is harder than what we were talking about

restive flare
#

my eyes are tired from looking at the diagram 😭

topaz sluice
topaz sluice
restive flare
#

im in year 10

topaz sluice
restive flare
#

omg how are you guys doing so much 😭

topaz sluice
#

Ill ask my friends tommorow to solve it

topaz sluice
restive flare
#

I am asian too 😭

#

maybe yall are in some elite school or smth

topaz sluice
restive flare
#

Malaysia

topaz sluice
restive flare
#

But I go to a private school so ig its different

restive flare
topaz sluice
restive flare
#

wow

topaz sluice
#

For some good student in my school , this problem is ass

restive flare
#

wow im from a private school and we're still doing algebra 😅

topaz sluice
restive flare
#

arithmetic to geometric mean

topaz sluice
restive flare
#

idk like differentiation

#

and turning points

topaz sluice
restive flare
#

have fun

wintry kiln
#

I have a trig test on Friday

#

and I think I’m gonna fail

#

💔

#

(I’m a fool for taking AP precalc)

#

My main problem is applications, graphing, and memorizing the unit circle.

unborn crest
wintry kiln
unborn crest
wintry kiln
#

TY PLS SEND

unborn crest
#

HELP MY BAD

wintry kiln
#

Microsoft teams go crazy

unborn crest
#

HAHAHAHHAHAHAH 😭😭

#

in trig we just did unit circle quiz

unborn crest
wintry kiln
#

TYSMMM

unborn crest
#

YWWWWW!!! 🤍 🤍

thorny cobalt
# dark sparrow gotta exercise GREAT caution even then.

It has helped me understand so much I am in calc 2 now, I used to struggle with intermediate algebra even. It has not led me astray in its explanations, I just feed the lecture material I am given and have it reexplain it in a way that I can understand.

narrow drift
#

Can someone explain how to solve "Beginning with the graph of f(x) = x2, what transformations are needed to form g(x) = –(x – 6)2 + 3?"

past rivet
#

i already did part 1 & 2

#

someone helped me with part 3 in a different server and i did that but i’d like it to be checked just in case

strange solstice
sweet spruce
#

Im having problems with polygon formulas can any1 help me

narrow drift
strange solstice
strange solstice
narrow drift
#

I wasn’t understanding what they meant by the question but I get it now

#

Thanks though

lucid panther
#

hello

#

i'm having a bit of a trouble with factoring and completing the square method

#

can some one pls help me

thorny cobalt
obsidian harness
# lucid panther can some one pls help me

This algebra 2 video tutorial shows you how to complete the square to solve quadratic equations. This is for high school students taking algebra and university students taking college algebra.

Algebra Final Exam Review: https://www.youtube.com/watch?v=U0Y8nSmEpNM

Quadratic Equations - Free Formula Sheet:
https://www.video-tutor.net/...

▶ Play video
#

try watching org chem tutor

#

you didn't say which level you were so this has some harder examples

#

also try Khan Academy for practice

#

you also wasted a lot of time by not posting a specific question that you're having trouble with

past rivet
worn lagoon
#

mentioning taylor series in a hs level geometry channel 😭

trail tendon
upper karma
#

Puhlease

#

What is the answer man

olive raven
#

can i pay someone to help me right now PLEASE PLEASE

half bone
#

isnt there a help channel?

timid fulcrum
#

I saw this one r/math

#

u/lucasvb claimed that you can extend to 3d trig functions, especially with steradians

#

but i have a feeling sine and cosine are sort of dimension-independent, so are functions like trig3d_x(ω,Ω) not quite right?

#

the user's comment was the highest, but idk if it's correct

upper karma
#

it turns the function to sqrt(sin(x)cosh(z)²+cos(x)sinh(z)²)

#

also the 3d parametric (sin(t),cos(t),t)

knotty jacinth
obsidian harness
knotty jacinth
#

180

#

so we solve for 180

obsidian harness
#

so what would the left hand side be then?

knotty jacinth
#

9x+54=18-

#

180-54

#

=

#

126

#

126/9

#

x=14?

obsidian harness
#

yep!

knotty jacinth
#

ok thanks

obsidian harness
#

,calc 31 + 9 * 14 + 23

somber coyoteBOT
#

Result:

180
obsidian harness
#

you can check yourself also, but yes

obsidian harness
knotty jacinth
#

How to do this?

#

solve for 180

#

but is CG X?

dark sparrow
#

no, CG isn't x.

#

you're told CH bisects arc DHG.

#

do you know what the word "bisect" means here?

knotty jacinth
#

yes

#

split in half

dark sparrow
#

yes, so

#

what must arc CG be then

knotty jacinth
#

14x-2?

#

wait

#

nno

#

7x-1?

dark sparrow
#

it must be equal to the other half of angle DHG, yes.

#

so 7x-1.

knotty jacinth
#

oh ok thanks

sweet basin
#

how do you do inverse trig ratio??

#

nvm

terse sphinx
#

can someone explain what's the difference between the sine rule and cosine rule? im having some difficulties understanding those

sweet basin
#

the sine is lenght of opp site side from the angle over the length of the hypotunuse

#

and the cosine is the lenght of the adjcent side to the given angle over the length of hypotunuse

#

sine is opposite/hyp and cos is adj/hyp

#

tan is opsitte / adj

sweet basin
#

Sine Oppisite Hypotnuse

#

and etc

terse sphinx
#

alrighty

sweet basin
#

get it

#

bro i got a trig test tmmmrw i just learned all this stuff now

#

im so cooked

terse sphinx
#

nah my final exam is next week

#

jus started g9

terse sphinx
#

it's just im having difficulties finding the edges or angles of those triangles where there's no right angle

#

they use some kind of Sine Rule and Cosine rules

#

like sine rules
a/Sin A= b/Sin B=c/Sin C

#

type stuffs

obsidian harness
#

for SSS, SAS you use the cosine rule

#

for ASA, AAS you use the sine rule

obsidian harness
#

there will be two possible triangles, with angles x and 180 - x

#

for example

terse sphinx
#

go on

obsidian harness
#

is there an example problem you'd like me to look over?

terse sphinx
#

my bad

terse sphinx
obsidian harness
terse sphinx
#

oh wait

#

ah i got it

obsidian harness
#

,w arcsin(10 * sin(33 deg)/6)

obsidian harness
#

damn it's in radians

#

but do you get around 65.2 and hence 180 - 65.2 = 114.8?

terse sphinx
#

damn

#

chat am i cooked 💔

obsidian harness
#

yeah then a good exercise would be to figure out the third angle

#

and then hence use the cosine rule to find B'C

#

or BC

high wadi
#

Can someone tell me why this equals 28ft^2, I got 32ft^2 by using the Surface Area formula to find it but it’s wrong somehow, is it 28ft^2 because it says that there is no lid?

signal vapor
#

It is an open box so the area of 1 side won't be counted

dark sparrow
#

that's why the area of the top face shouldn't be counted.

median whale
#

could you send image

#

@lilac bridge

silent plank
#

that's calculus, not geo/trig,
post under the appropriate channel topic or claim your own personal channel #❓how-to-get-help

solid needle
wanton ember
#

5

#

yeah because each time it accelerates it ignores x^9 so that can cause the number to concept to the power

trail tendon
#

where in Norway

#

more like a geology question bleak

#

4.91300

#

why does he ping so weirdly

#

why not bro

#

do you not agree that norway is a big rock? bleak

#

😂

upper karma
#

Lmfao

#

Nah man this chat funny

rotund arch
#

Hello everyone, my name is Alan and I'm from Brazil, I passed the math exam at Unesp here in the state of São Paulo and I need to study for a trigonometry test in about 4 days. What do you recommend?

#

For me to study for this

#

I started finishing the semester and I'm asking

upper karma
#

I recommend studying trigonometry

rotund arch
upper karma
#

Nah wtf

rotund arch
#

I don't know

upper karma
#

Nah man homie changed name for answer is crazy

#

☠️

#

I can’t stop laughing this is crazy

#

Lmfaooooo

#

Why u both got same sentence lmfao

upper karma
#

Is free

#

With no ads

#

I suggest that

#

What happened here bleak

#

U three back

topaz lava
#

What’s the hardest thing it geometry and how do I prepare for it next year

bleak blade
signal vapor
#

How should I study from Euclid's elements

#

It is way too complicated

#

Is there a similar book slightly easier to understand

cunning lion
#

there are plenty of proof-based high school geometry books which present most of the same content in a more digestible format

signal vapor
#

Any particular one which I can refer

half bone
#

idkk

#

but i heard of uhhh

#

wait lemme gg it

#

theres a series of books by j. e. thompson called "mathematics for self study", tho it covers multiple branches. you might wanna check it out.

half bone
uncut crest
stiff yoke
#

So

#

Scale factor = 15/12

#

=5/4

#

1056pi • (5/4)^2 = 1650pi as your surface area.

#

For C-B

#

Volume: 4608pi • (5/4)^3 = 9000 pi

#

May be confusing since it’s a mix of 2 different concepts.

#

@uncut crest

uncut crest
#

K thx

#

I was told by my teacher to square for SA and cube for V but I didn’t know what to square and cube

lapis moon
lime crownBOT
stiff yoke
#

!noans?

lime crownBOT
#

The purpose of this server is to help you learn, not to hand out answers. Do not ask someone to give you the answer directly.

stiff yoke
#

@lapis moon

stiff yoke
#

I’ll explain in depth next time

meager sinew
#

just use wolfram alpha

stiff yoke
#

What?

lapis moon
# stiff yoke ?

Instead of a complete solution, give the question asker hints/guide, so as to leave a room for them to solve their own question themselves
That would allow them to learn by doing instead of passive learning

obsidian harness
#

<@&268886789983436800>

dark sparrow
stiff yoke
#

!nosols

lime crownBOT
#

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.

deft peak
stiff yoke
#

Do you have any more of these for different concepts by any chance

#

Or where did you find these?

deft peak
deft peak
#

Do u need by any chance?

#

I have got kepler and dual nature of light

#

Three videos have been uploaded

stiff yoke
dreamy ferry
#

Can I find the area of a triangle knowing three sides, but no height

exotic yarrow
#

Look up Heron's formula

dreamy ferry
#

awww man I can't use that, this means I have an entirely different problem

exotic yarrow
#

You could always find the height yourself catshrug

#

Find one angle using trig and then do trig area

dreamy ferry
#

Yeah just wondering how to do it

exotic yarrow
#

Put it in coordinate space and shoelace or draw a rectangle around the triangle

#

Use extended sine rule to find the circumradius and do A=abc/4R

#

etc

pure steppe
#

is this accurate or not

runic pasture
#

yes

tropic karma
#

GUYS can anyone please explain?

pallid smelt
kindred onyx
#

For the first one

#

This is how I solved it. First, i tried finding the reference angle. We are given that $$\cos \theta = -\frac{1}{\sqrt{2}}$$. The reference angle is the angle whose cosine is $$\frac{1}{\sqrt{2}}$$. This is a special triangle value, and the reference angle is $$45^\circ$$

somber coyoteBOT
#

Jesuslover123

kindred onyx
#

Next, determine the quadrants.

#

Since $$\cos \theta$$ is negative, $$\theta$$ must lie in the second or third quadrants.

somber coyoteBOT
#

Jesuslover123

kindred onyx
#

Thirdly, find the angles in the second and third quadrants.

#

In the second quadrant, the angle is $$180^\circ - 45^\circ = 135^\circ$$In the third quadrant, the angle is $$180^\circ + 45^\circ = 225^\circ$$

somber coyoteBOT
#

Jesuslover123

kindred onyx
#

And lastly, consider the range 0⁰ to 360⁰.

#

The angles that satisfy the equation $$\cos \theta = -\frac{1}{\sqrt{2}}$$ in the range $$0^\circ$$ to $$360^\circ$$ are $$135^\circ$$ and $$225^\circ$$

somber coyoteBOT
#

Jesuslover123

kindred onyx
#

Hope this helps!!! I tried my best

tropic karma
deft peak
#

Eh

dark sparrow
#

compare: this is an inline formula $x^n+y^n=z^n$ while below is a displayed formula: $$e^x = \sum_{n=0}^{\infty} \frac{x^n}{n!}$$

somber coyoteBOT
kindred onyx
summer cradle
summer cradle
stiff yoke
#

@somber coyote

stiff yoke
# tropic karma GUYS can anyone please explain?

Here’s how I solved it

  1. Initially, My goal was to use inverse cosine. So,
    $$ cos^{-1 } (-1/sqrt{2}) $$

The answer would be 135 degrees

Now you take 135 and subtract by 360, since you need cosine to be negative. X= -cosine
Answer would be 225

somber coyoteBOT
#

Immanuel-TP

stiff yoke
#

This works because Inverse Cosine gives us our main output as the unknown angle since we know 2 sides of the triangle.

lapis moon
lime crownBOT
stiff yoke
lapis moon
#

when explaining, give hints/guide, which is a global description of the detailed steps

#

and leave OP a chance to work them out

lime crownBOT
lapis moon
#

please let the question asker to do their HW honestly
instead of giving the answer directly

blazing bolt
#

does anyone wanna do some trig? i wanna learn but it's hard to focus alone (ADHD)

spare nova
#

how do you solve for the red area ive been trying to do this for a while but i cant crack it

stiff yoke
#

Wow

lapis moon
# blazing bolt does anyone wanna do some trig? i wanna learn but it's hard to focus alone (ADHD...

here's a youtuber and a former math phd student having adhd
https://youtu.be/-wf1M9oABX8?si=Dx4ECCwXpidEuoxy

I overcame my ADHD with THIS study method! How do Harvard and MIT students study? How to effectively memorize without forgetting? The most effective evidence-based memorization method. Why memorization is key for studying, even if you're a STEM student. How to use Anki?

▬ In this video ▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬...

▶ Play video
spare nova
#

can someone solve it tho

#

legit nothings worked so far

brisk abyss
#

the area of the semicircle is 25 pi upon 2

#

Sooo

#

the red area is about half of the semi circle

#

i think it could be 25 pi upon 2 into 1 upon 2

#

Thats 25 pi upon 4

#

@spare nova

#

Thats a really cool quesiton tho

sage radish
sage radish
sage radish
#

Nevermind i was wrong

#

its 25*arcsin(1/4 root(14)) -100arcsin(sqrt(14)/8)+25/2 *sqrt(7)

graceful talon
#
its 25*arcsin(1/4 *root(14)) -100*arcsin(sqrt(14)/8)+25/2 *sqrt(7)
sage radish
#

thanks i cant format for my life

covert pewter
weary bough
#

Hello guys u clean wondering if anyone could help not sure which 2 i got wrong

summer cradle
#

the bottom one should be 3.5sqrt(3)

#

unless the solid is not a prism

summer cradle
grizzled hull
#

I have a question everyone

#

is similarity of triangles an equivalence relation?

#

actually no im stupid thats not what i meant to ask

#

is it transitive?

dark sparrow
grizzled hull
#

im thinking that it is

#

but thats a hunch

dark sparrow
#

try to sit down, write out properly what it would mean for the similarity relation on triangles to be transitive, and attempt to prove it

grizzled hull
#

alright gonna do it

grand path
#

Hello, i am stuck on a problem, and well, i don't even know where to start...

Here's the problem: we have a triangle ABC that is equilateral whose side is a (a strictly positive) . is the symmetric of C by the point symmetry of B. We draw the line (delta) which passes through P, M which is on [AB] and N which is on [AC] . We say that BM = x.
What is x for CN= 2a/3.

#

Here's a drawing of the problem:

#

And well.... i don't even know how to express the relation between x and CN so here i am

#

Does anybody have a way to start on this problem?

brisk abyss
lapis moon
somber coyoteBOT
lapis moon
#

Please rotate your picture, so that PC users can view it More easily

grand path
#

Sorry

lapis moon
grand path
#

Seems like something new to learn, thank you

sage radish
brisk abyss
#

Pi r square

#

25 pi

#

oh im wrong!

sage radish
# brisk abyss If create a circle outside with a radius 10 then the circle ( red area ) could b...

In 2-dimensional geometry, a lens is a convex region bounded by two circular arcs joined to each other at their endpoints. In order for this shape to be convex, both arcs must bow outwards (convex-convex). This shape can be formed as the intersection of two circular disks. It can also be formed as the union of two circular segments (regions betw...

#

crazy formula: area of circle - lens = area in problem

rain jolt
#

can I use the law of cosines for any triangle?

#

does it matter if its obtuse or acute?

cunning lion
#

yes, any triangle

rain jolt
#

thnx

timid fulcrum
#

has anyone came up with a geometric interpretation of say the derivative of surface area? I'm not talking about seeing things as rates of change

#

for a sphere that is

#

im just curious because since SA is V', then what does SA' mean?

#

and the reverse: what does ∫Vdr mean?

cunning lion
#

well $\odv Sr = 8\pi r$ which is four times the circumference of a great circle, i'm not aware of any further significance. a more natural connection is that the derivative of a circle's area with respect to the radius ends up being the circumference

somber coyoteBOT
cunning lion
#

the integral of the volume with respect to radius would be some sort of 4-dimensional hypervolume quantity

timid fulcrum
#

yeah, just not the actual hypervolume. aka $\frac{1}{3}\pi r^4 \not = \frac{1}{2}\pi^2r^4$

#

idk if there's really any analog for this quantity

cunning lion
#

on the earth an example would be the equator

#

basically any circle which divides the sphere into two equal hemispheres

#

so it shares the same radius and center as the sphere itself

somber coyoteBOT
#

TooMuchofEverything

cunning lion
#

well you wouldn't necessarily expect that integrating the volume of a sphere to give the hypervolume of a hypersphere, just like how integrating the area of a circle doesn't give the volume of a sphere

timid fulcrum
#

yeah

balmy furnace
#

hey...im new to discord ...wont mind having friends here 🙂

slender bronze
#

Do you guys think i'm good ?

upper echo
empty yew
#

How to find the principal solution from 0 to pi for tan(x)+sec^2(x)=1 ?

#

ping me if anyone know how to find this.

summer cradle
spiral lodge
empty yew
#

tan(x)(1+tan(x))=0 then x=0 and sin(x)+cos(x)=0 what to do here?

summer cradle
#

and also you don't need to convert to sin and cos for the 2nd

#

just simply 1+tan(x) = 0

#

so tan(x) = -1

empty yew
summer cradle
empty yew
#

pi/4

summer cradle
#

yes

#

now cuz this is -1 instead of 1

#

and x ranges from 0 to pi

#

in which quadrant is tan negative?

empty yew
#

second and fourth

summer cradle
#

correct

#

but in this question we choose second

#

cuz 4th is out of range

empty yew
#

tan(pi-pi/2)?

summer cradle
#

no

empty yew
#

tan(pi-pi/4)?

#

x=3pi/4?

summer cradle
#

tan(pi - a) = -tan(a)

#

right?

empty yew
summer cradle
#

previously we know tan(a) = 1 and a = pi/4

#

so sub that in

empty yew
#

@summer cradle isn't tan(x)=0 at two x's?

#

x=o,pi

#

then x=0,pi,3pi/4

#

is this correct?

summer cradle
summer cradle
empty yew
#

ok thank you so much @summer cradle

#

@summer cradle do you know about conditional trig and determinants?

summer cradle
#

and what's conditional trigonometry?

#

never heard of that term

#

maybe give an example

#

I may know it but only didn't knew the term

empty yew
#

A+B+C=pi and some equation to prove using this condition

summer cradle
empty yew
#

I want to solve this

summer cradle
empty yew
#

np

patent juniper
empty yew
#

that's too tedious using formula I want to find the determinant using properties and conditional trig directly

obsidian harness
#

$\sin^2 B \cot C - \sin^2 C \cot B - \sin^2 A \cot C + \sin^2 C \cot A + \sin^2 A \cot B - \sin^2 B \cot A$

somber coyoteBOT
obsidian harness
#

tedious no matter what you do

solid needle
#

it turns out the coordinates here are real so they form a degenerate triangle, but there does exist a transformation to get from one to the other

#

hint: ||you need a reflection and a dilation||

#

(matrix is sideways but reorienting it is trivial)

#

this what you're looking for?

empty yew
#

I can't understand what you're trying to say.

solid needle
#

or is your confusion about how to apply this idea

#

am i misunderstanding you?

vapid gust
#

according to skibidi of the tangent, the sin of 40 degrees is hawk tuah gyatt

timid fulcrum
timid fulcrum
glacial ember
#

chat this triangle is impossible right

#

cuz of triangle inequality theorem?

summer cradle
cunning lion
#

not strictly impossible but it would be a degenerate triangle (overlapping line segments)

fallow prism
#

is gpt wrong here?

#

the number atthe end of the sinus equation or function i dont know im not english is +1 (vertical movement) so from what ive learned in the last 4 hours shouldnt the line start from 1 rather than 0?

#

pls someone help me its 4am i wanna learn this and go sleep 🙏

#

@cunning lion do you know?

cunning lion
#

if you want to plot a function and get an accurate plot i would recommend desmos

#

chatgpt doesn't inherently "know" what a function looks like so it just plotted y = 2sin(x) because it has the more classic "sine shape"

fallow prism
#

i haveno clue how this happens becuase apparently the +1 at the end i think that would mean it starts from 1 not 0 or -1

cunning lion
#

if you plug in x = 0 you get 2sin(0 - pi/2) + 1 = 2*sin(pi/2) + 1 = 2(-1) + 1 = -2 + 1 = -1

fallow prism
#

ah

#

and it starts with x axis 1 and y axis -1 too

cunning lion
#

the +1 determines the midpoint line that the sin oscillates around

#

so the midpoint line is y = 1 in this case

fallow prism
#

whast the midpoint line im sorry i learned math terms in croatian

#

oh the average

#

OHHHHHHHHHHHHHHHHH

#

I GET IT

#

I LOVE U @cunning lion

#

❤️

#

so it does start in Y=1 but just x is moved 1 to the right im so stupid

errant hedge
#

hey does anyone know how you can get angles BAD and CAO are equal right off the bat for this problem?

nocturne wren
empty yew
solid needle
empty yew
#

yes

solid needle
#

ok then so

#

i posted an answer already and all you said was "i dont get it"

#

can you be more specific about what you dont get

solid needle
#

ok....?

empty yew
#

I didn't understand the sentence you said there

solid needle
#

this is really tiring, i dont know which sentence youre referring to, please be more specific

hexed sand
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i'm not sure if this is the right place to ask but why are trig functions the way they are? i understand that sin(x)=o/h etc. but i don't understand why they are defined like that

obsidian harness
hexed sand
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this is my first message on this server

dark sparrow
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are you asking where their names come from?

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or are you asking why we care about side ratios at all in the first place

hexed sand
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i guess what i'm asking is what actually is sin cos tan and where did they come from??? (i'm not that experienced in maths so i only know sohcahtoa and a bit of sin rule and cos rule)

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sorry if im not being specific, idk exactly how to articulate what im asking

dark sparrow
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A) "Why are sine, cosine and tangent named this way? Who came up with those words?"
B) "So... why do these functions matter exactly? Why would we care about the ratio of some sides in a right triangle?"

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is your quandary more like A or more like B

hexed sand
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mostly A, a bit of B???

dark sparrow
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ok right

hexed sand
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sorry i realise im being not very specific

dark sparrow
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no actually i have just the thing.

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essentially, sine is kind of the result of a centuries-long game of broken telephone involving Sanskrit, Arabic and Latin

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but at its roots the idea is that of a right triangle inscribed into a circle, and mirrored across one of its legs, so that the doubled opposite leg and the circle arc kind of form something that looks like a bow

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the co in cosine stands for complement, in the sense of 90° - x

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(so like, the identity cos(x) = sin(90°-x) is kind of what gives cosine its name)

hexed sand
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fair fair

dark sparrow
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tangent is more directly from the latin word for "touching" (in fact we still use this word for a straight line that touches a circle)

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it and secant are best understood in the context of the unit circle

hexed sand
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thank you very much!

dark sparrow
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like this

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secant means "cutting", and etymologically is related to words like section

manic ridge
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if have the adjacent how do i find the opposite it is adjacent x tan (angle) or adjacent / tan (angle) or smth else

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cuz i lowkey kinda forgot

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nvm got it

river viper
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what would this triangle look like
Given triangle ABC, we find the median AM and the distances BD and CE of the vertices B,C from AM to be
i mean where would you place points D and E?

lime dune
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extend AM and drop perpendiculars from B and C

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their intersections with AM are D and E

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when we say “distance from a point to a line” we mean the perpendicular distance

tepid otter
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Can someone explain to me how to solve trigonometry i mean how to use the formulas of trigonometry