#geometry-and-trigonometry
1 messages Β· Page 27 of 1
wait how old r y'all that's the main q
cuz
grades are diff in some countries
I'm 15
same-
Well I'm 16
cool cool
yeah no I was feeling hella optimistic when I started this
but these equations hella complicated
bruh this is gonna be a biquadratic equation wth

same
niceeeeee
people at #competition-math might solve it in <10mins lmao
Damn fr?
I ain't gon touch that place then π
I wouldn't say I'm excellent at maths I'm just interested
imma
post it there
too
π
Aight lessgo
alr then
OH YEAH JUST SAW THAT
I first saw the last question there
and was like eh easy stuff
then I decided to scroll up a lil
π
big mistake
wait till u join the math olympiad server linked there
π
fr
hell naw
dont feel demotivated tho
my mental math sucks man
YOOOOOOO
they really just do such maths in a deeper level
Which one
I c
numberphile
n mind ur decisions
π
fax
ig mind ur decisions will prolly reply faster
seems like a video worthy question if it's even solvable
i hav an eng exam tom
and here i am doin
a hard ass
geometry q
π
LMFAOOOOOOO
I almost failed my social studies exam
cuz there were some pages in between
that didn't have lines
i hate sst
so much
hist cant get into my head
and I kinda discovered a new way
to do this trigo question
So I started doing tht instead
π
OMG SAME
so much memorizing
I got 0.5/20 in history
but I managed to pass thanks to the other 3
bro
π
fr
i have 45/80 in sst
and 80/80 in meth n sci
tht too 45 cuz
eco carried
hist i got 5 or smthin
I messed up science again man
just can't get myself to memorize bio
I can't memorize anything
on the brighter side if we just compared physics I got the second highest in my class
one mark difference between first and me
ye
bio
pain
esp some of the long complex diagrams
cuz physics actually requires a lot more thinking and that's what I actually enjoy doing
not memorizing diagrams n shit
||hardcore math ppls de wonderin y we talkin abt bio n sst here since 10 mins||
fr
muggin up not my thing
LMFAO
should've switched to #discussion
lets just go there
too late
but sure
is this problem possible???
iβve been trying to figure it out for a bit. i donβt believe itβs possible
too many unknowns
I'll try it out
$\overrightarrow{OP}=(3,-1) \implies \overrightarrow{PQ}=(1,3)$
Civil Service Pigeon
oq isn't given tho?
huh
use distance formula
make an equation containing the variable 't' using this
sorry for the bluriness
wow thats more complex than i'd imagine
basically, since RQPO is a rectangle, then OP is perpendicular to QP.
so, (m_OP)(m_QP) = -1; where m = slope
from origin (0,0,) we can find the slope of line OP, giving us -1/3. Substituting to the equation earlier, we get:
(-1/3)(m_QP) = -1
(-m_QP)/3 = -1
(3)(-m_QP)/3 = -1(3)
-m_QP = -3
m_QP = 3. So, from P (3,-1), we can use the slope of QP to find the coordinates of Q. Q (x_P +1, y_P+3) = Q(3+1, -1+ 3) = Q(4,2) Hence, t = 2
what do they stand for?
how can i study trigonometry properly?
been trynna understand trigonometry for a decent amount of time, i think im pretty decent with the simplification but when it comes to questions with unit circle i literally cannot move my pancel, any tips or tricks?
Mark the centre of the largest semi-circle (midpoint of the radius 2). Recall that in two tangent circles, the line joining the centres and the point of tangency are collinear. Hence, join the centre of the third circle with the other three centres. Then you get a triangle with side lengths: 3, 2+r, 1+r. Then join the centre of the complete circle with the centre of the largest semi-circle. Since these two circles touch internally, the distance between their centres is just the difference of their radius. Then you can apply stewarts theorem. This yields the quadratic equation $$ 6 + 3(3-r)^2 = (2+r)^2*(2) + (1+r)^2(1) $$, this giving $$ r = \frac{6}{7}$$
Barycentre
this is the millionth time I'm asking this, but is there a standard name for the property of the height, angular bisector and median of an isosceles coincides / being the same?
nice
Im just beginning geometry. For x I got 8 square root of 5. And somehow for y I got 96 square root of 5. Please help
!show
Show your work, and if possible, explain where you are stuck.
For x, u r right
But for 'y', u have to show that KNL is simillar to KLM
M
now try to find the side lengths now that u have ΞΈ
Let $\theta_1$ be one angle in a right triangle and $\theta_2$ be another angle in a right triangle. $\theta_1=90-\theta_2$ or $\theta_2=90-\theta_1$
saddayyy_
This is because the sum of interior angles will add up to $180^{\circ}$ in a triangle and with a right triangle, you already know that one angle is 90 so $\theta_{a}=180-90-\theta_{b}=90-\theta_{b}$
saddayyy_
why bother explicitly getting the third angle when you could use the given 67Β° angle directly
is there a proper name for the property of isosceles triangles having height, angular bisector and median to the base coinciding / being the same?
did you mean cos 30 or cos 30 degrees
Recall cos(30 degrees) = cos(pi/6) = sqrt(3)/2
I suggest you read up https://en.wikipedia.org/wiki/Radian
The radian, denoted by the symbol rad, is the unit of angle in the International System of Units (SI) and is the standard unit of angular measure used in many areas of mathematics. It is defined such that one radian is the angle subtended at the centre of a circle by an arc that is equal in length to the radius. The unit was formerly an SI suppl...
no
yeah just read the proof of how 30 degrees right triangles have hypotenuse = 2 opposites (slice equilateral triangle in half)
is it better to answer 138 degrees or 222 degrees for this question: "what is the standard position, 0 < ΞΈ < 360, if 42 degrees is REFERENCE angle."
would 138 be a better answer or 222 im so confused both have same reference angle
is that the full question/exact wording?
What you can do is take the arc cos and arc sin to find the angles of the enscribed triangle and find the missing side length of that enscribed triangle. Then when you get your angles you can apply even more trig to find the adjacent sides to get the length of AD
Did this for a project, all I needed to do was the streets and place buildings on angle pairs and color it, but for some reason I decided to go overboard and make a whole island lol
I found this exchange online https://math.stackexchange.com/questions/3575601/if-the-median-and-bisector-of-one-of-its-sides-of-a-triangle-coincide-then-the So I think if the triangle's median and bisector coincide, then it's an isosceles. Could the proper name be "isosceles triangle's property"?
interesting
I think the question lacks conditions, the shape isn't fixed. You can rotate the inner triangle and get a different square, or since the included angle by 12cm side and 13cm side isn't given, you can easily get different squares from that.
e.g. I can literally just stretch the two sides flat and make it almost a degenerated triangle (a straight line) and make a square much larger
could be good source for my fantasy world building, yoinked (jk)
wot
||people make fantasy maps for fun||
o
im in the middle of my last question or two for geo hw rn
its 2:51 and i got math class tmr lmao
2:51 am
extra outside of school math classes
I got that 2 times a week
2 hrs each class
and I also gotta go to english for a hr 2 times a week
I dont even have english or math first sem
Yo am I correct on this question
bro i dont get your thing and i havent studied trignometry
uh i got 64.87 degrees idk if i did something wrong
I just used the fact that triangle HAF is isosceles
It is 64.87
I think you just use the sine law
Bro i forgot about the sine law
Where side A is opposite to angle a, and so on
As i remember, there needs to be 1 angle which is a known value for the sine rule to work
Whereas there are no known angle values in the question i had
The fact that the triangle is isosceles and you know all sides
I think that's enough
Also how did you get that arccos expression
Whats arccos
cos^-1
Oh thats from the cosine rule
How is your other side 6
?
@honest loom
What triangle did you apply the cosine rule on?
Ping me when you're here
ig triangle FBA
oh sorry i dint see that
anyone help
how'd u get 5?
and is this angle given as = 90deg or u assummed it?
given
its a G
Bc you just apply formulas lol
if I know:
its a triangle
b=2
c=2
B=75.52248781407
C=75.52248781407
what is the formula for a? (small letters are sides and big letters are angles)
nevermind I got it
is law of sine this unaccurate or did i mess upp something?:
for a I got 0.691302064481663
I did sin(B)/b-sin(A)
I'm in college and doing gcse maths in one of the lessons, we were doing geometry and one of the questions was like this
I didn't really understand the theory
I hadn't done stuff like this in years and I may have already forgot some of yesterday
I got some of the stuff like uuuh this would be 5 x 2 = 10 and you divide that by 2 and you get 5
This should be an obvious one but what is the term to refer to what you're calculating here?
Something like area right?
maybe put labels for the vertices to get those side values clear, and also properly distinguish what that "?" is for
calculating its area yeah
what's the vertices again?
area units
vertex (single), vertices (plural form). Each vertex of a polygon e.g triangle refers to its corner or point of intersection of the lines or the polygons' edge. Thus, enclosing the figure
so is vertex a side?
it's a vertex, lol
nope, its corner basically
look it up
so it's a corner
yeah
so on that rectangle there is 4 of em
the question was the line with the ?
Idk how to judge that one
The shapes weren't specific, just generic and given numbers
So we weren't using equipment to find out
sorry but I didnt get what u asked
we have to guess that number
which?
the line in the triangle
can u share it again, but with labeled vertices? So we can distinguish what u're tryna find
like this?
like put A,B,C,D etc to name those corners
?
you're missing 1 vertex in there
try to observe the figure
hint: there are in total three triangles, but this line divides the biggest into two smaller ones.
Three triangles?
again, observe the figure and try to see it yourself
It is not a triangle, it is a pyramid (3 dimensional), try to look into it deeper because you are viewing it as a polygon and not a polyhedron
is it a isosceles triangle?
is the line meant to indicate that?
couldnt be too sure, he hasn't stated what description the triangle has
I just drew that on paint, it was what the question looked like
the numbers aren't exact either
honestly tho, u should try looking up geometry lectures first
coz u seem to have forgotten the basics in geo
khan academy is a good way to go
I don't really know what else I could say, there were triangles with marked corners and numbers on the sides
It is a three dimensional figure on a two dimensional plane
The black is the base, the red are the parallel faces.
It becomes much easier to identify them if you draw them properly
Although my drawing is horrendous too
But as you can see, there are 3 parallel faces and 1 base
4 vertexes in total
Vertices*
i dont think these directions would help him understand the basics of geo well enough
especially when "parallel faces" could have more formal terms
Of course not, but I think if he realizes what he needs to look for then he can engage with future material better and know which direction to go in
Best would be to do Khan Academy or formal resources
yeah, but not when he doesnt even know what terms/concepts we're plugging into him
@remote herald The answer is : (AD=12.6cm). Hints: find congruency in triangle GAE and triangle GDF and also use trigonometric ratios and Pythagoras theorem. I π encountered with geometry after 6 yrs, still fun.
and our own interpretation of the terms might confuse him in other stuff
Yeah, he definitely needs to go back to Area and improve those foundations
I don't really understand all the lingo
I forgot pretty much all of this stuff I learned in hs
Why did I say parallel faces
I meant to say lateral lol
I just realized
yep
hence why he should go to khan first, lol
Yeah, but I'll try giving him a rundown because I know when I first learned it I could not even understand how to tell pyramids from prisms apart
So, the Base is the base (shocking). Think of a house. It has a floor (the base) and a ceiling [also a base, they are parallel (parallel means is that they are opposing one another) and congruent (which means equal)]. The lateral faces would be the four walls of the house, assuming the house is cube shaped.
Another example: In a square pyramid, the square would be the base and the lateral faces would be the triangles. There would be a total of four lateral faces (in this case, in pyramids, triangles) because a square (the base) has four sides. You identify pyramids by the base, by the way.
I think these two terms are pretty self explanatory though, some figures have two parallel and congruent (equal) bases such as prisms (like the house example above).
Some do not, like pyramids, they only have one base. As used in example above.
A way to identify whether a solid (a three dimensional figure) is a pyramid or a prism is pretty easy.
If the lateral faces are parallelograms (a type of quadrilateral, which means a four-sided 2D figure), it is a prism. If the lateral faces are triangles (three sided 2D figures, not 4), then it is a pyramid.
Holy shit explaining this is so hard
I can try help answering some of your questions if you have any btw. Just ping me, but just like the others above definitely check out Khan Academy, or The Organic Chemistry Tutor (a YouTuber who is awesome).
still you made it like a prof.
Thanks π₯Ί
I'm sorry if this is a silly question but is there like a test paper where it explains the theory of the following questions?
You know how like a test would in school?
I always employ the Feynman Technique while studying, even in math. So I try to simplify it as much as possible to be as digestible as possible
And remember dude, mathematics builds upon itself. If you don't know how to add or subtract (the theory), multiplication and division is very hard. So since you struggle with 3D figures, go back to 2D such as identifying them, areas etc.
I don't think there was any implication of 3D shapes
The problem you had involved a three dimensional figure
It was a triangle with a line in the middle, all of the prior questions were squares/triangles with numbers on the sides until that point and you calculate the area
Yeah, it was asking about the Base
Two Dimensional figures do not have bases, only 3D Figures do
Not sure what exactly it was asking about, but it was definitely the base
Many books, Khan Academy and YouTube videos. I cannot really recommend a text-based one as I used a book which I assume you do not have access to. I would definitely check out Khan Academy and The Orgo Chem. Tutor as I said
Can you resend it
Oh, yeah. Definitely 3D. You just cannot draw a line connecting the third vertex because it overlaps with it
I am not sure whether it is asking about like the...area of the base or the length of that side though. But it is definitely three dimensional
The rest of the questions were about area so this has to be area too for sure
Then it is asking about the area of the triangular base
But the shape itself is three dimensional
add more details
^ like I do not know what the problem is. Are you asking about how to calculate the area of a triangle or?
If it is to calculate the area of that triangular base, you just do 1/2bh
Yeah it's the area
Okay, so you don't know how to calculate Triangle Area, that's the problem right?
The others went like this
50 x 25 halved makes the area
I did the other triangle areas fine it's just that ONE question had a line in the middle with a ?
So I figured I gotta get the value of that line
Not going to lie dude, you cannot get either the line or the area of that problem because you do not have any values
Do you know anything about that pyramid? You need some actual numerical values to figure out the rest
You mean like the numbers in the question I'm talking about? I was throwing around generic ones (because I couldn't remember the exact numbers)
If I had to think real hard...
Woah, my internet is fucking up what the hell
@pliant nestwhere are you from?
Bro, why does the figure change every time? It is still a 3D figure, but now it seems like you are supposed to find C. For which you could use the Pythagorean Theorem (a^2 + b^2 = c^2) as opposed to finding the area of the base or something
I live in Europe
is the figure the number? last time i just threw 50 50 together just cuz, i think the exact numbers were 50 and 45
i dont have the exact triangle from the document so i draw what it looked like in paint
Nvm
You cannot use the Pythagorean Theorem on that triangle, that is not a right triangle
But now it seems like a different problem altogether nonetheless
the shape of the triangle doesn't really matter that much (as far as I know), the document just used generic shapes
You need some form of values. Length of sides, angles etc. to actually do anything with the image
So knowing that 1 side is 50 units, the other is 45 units
Does not really help because now it does not seem like you are supposed to figure out the area of the figure (to me at least). But the line that runs through the middle is there to represent that it is not a triangle (2D figure), but a pyramid (3D figure)
Idk how to help you dude. The formula to figure out the Area of a Triangle is 1/2(B)(h) or 1/2Bh
Khan Academy would probably help with this right?
Do what you can with that knowledge
Definitely
The line might actually not mean anything at all, but I saw it and I thought "wait... how do you calculate the line?"
Who knows, good luck though
most questions with triangles looked like this
no line in the middle
it's just one had that line in the middle that confused the shit out of me
Well, dude, if all the questions were about area then it was definitely to solve the area using the known values
okay im kinda struggling here, when im converting radians to degrees and vice versa
and i have a radian greater than like 2pi or degrees over 360 the formulas just kinda fall apart for me
like im trying to convert 14pi/3 to degrees and i get 840 degrees
but the correct answer is 120 degrees, and im clueless on how to get from 840 degrees (my answer) to 120 degrees (the correct one)
so i just simply subtract 360 from my answer until i get an angle under 360?
because that gives me the answer but i feel like im doing it in a wrong way
well consider what 14pi/3 radians really means, it's like doing 2 full turns and a bit
that "bit" just happens to be 120
for most intents and purposes you tend to want to find that angle, as telling us that the angle is 2 full turns and 120 is redundant when we can just say its a turn of 120
lmk if that doesn't really make sense
well i know what that means in the bigger picture
but when actually calculating that angle
you get 840, but 840 isnt really saying much
is it as simple as just subtracting 360 from 840 until it gets to 120?
basically yeah
oh, okay then lol thank you
all good!
i get what you mean though it doesn't seem particularily mathsy to just subtract until it works
omg yeah that always makes me overthink things
when you have a complicated thing you expect a complicated way of solving it
so when it's simple it just feels wrong at first
true true
Does anyone know why or how there are so many different forms of the angle bisector theorem?
Are the triangles themselves (formed by the bisector) similar?
and also does anyone know where BD = ab/(b+c) come from?
$BD = \frac{ab}{b+c}$
\begin{align*}
\frac{BD}{DC} = \frac{c}{b}
\frac{AB}{BD} = \frac{AC}{CD}
BD = \frac{ab}{b+c}
\end{align*}
\begin{align*}
$$\frac{BD}{DC} = \frac{c}{b}$$
$$\frac{AB}{BD} = \frac{AC}{CD}$$
$$BD = \frac{ab}{b+c}$$
\end{align*}
\begin{align*}
\frac{BD}{DC} = \frac{c}{b}\
\frac{AB}{BD} = \frac{AC}{CD}\
BD = \frac{ab}{b+c}\
\end{align*}
donut123
Just made this to help me remember the unit circle (excuse my handwriting)
An interesting mnemonic pattern I've seen used to remember the coordinates of the 0Β°, 30Β°, 45Β°, 60Β°, 90Β° points is:
(sqrt(4)/2, sqrt(0)/2) .. (sqrt(3)/2, sqrt(1)/2) .. (sqrt(2)/2, sqrt(2)/2) ... (sqrt(1)/2, sqrt(3)/2) ... (sqrt(0)/2, sqrt(4)/2)
but the precise angles that go with each of those would still need to be memorized separately.
guys i made parabola go spinny
Thanks a lot for your help
but i havent studied trignomerty
idk why but I simply just do some calculations to fill up the unit circle, lol. Like i never memorized the values at all
like from the special right triangls in the 1st quadrant, i can just find the corresponding angles in the other 3 quadrants and get the coordinates
I had something for you
Let me host it up wait
Alr ping me when you're here
I hope that's what everyone does. But at least the magical angle 30Β° for the one of the special triangles that's not diagonal is arguably something of a memory item too. Once you remember that the 30Β°-60Β°-90ΒΒ° triangle is the one whose ratios can be expressed with square roots, you can easily calculate what those square-root expressions are.
I suppose the physical work of drawing up the entire circle neatly with pen and paper can possibly be valuable for recalling the relations later on. The actual paper can be thrown out as soon as you can get it over your heart, but having done it helps remembering what it was you did.
I don't understand why i had to put my calculator in radians for this question.
Because that's the usual convention for angular velocities.
how is this angular velocity
id appreciate any help on this
The comment under the formula helpfully describes the cosines as $\cos(\omega t)$, and $\omega$ is the usual symbol for angular velocity. So I'd conclude that the $25\times 10^{-3}$ factor is a time in seconds (they speak about "25 ms" later), which would make the $200$ an angular velocity of 200 radians per second.
Troposphere
so is if it was in degress would it have the degree sign and when not it is radians
It more like it's conventional not to use degrees for angular velocity at all. If you want to describe the speed of rotation in something where whole revolutions are nice numbers, you'd be working with frequencies (f) instead of angular velocities (omega).
ok, I'm digesting what you said and how to apply it what I am learning. Thank you for your help!
It's not unlikely that somewhere above what you showed, there's something that makes it more obvious that the number 200 is given in radians per second rather than degrees per second.
However also perhaps not, since this seems to be electronics. Generally numbers you find by calculating with capacitances/inductances will naturally come out in radians rather than degrees.
This is the original question
Unfortunately Iβm weak it my understanding of some math concepts. Iβm just beginning circuits 2. So I donβt understand when itβs in radians or why
Okay, then your only hope seems to be to know the convention.
In general, any number that you multiply by an amount of time to get something you then stick into a trig function is an angular velocity, and the convention is that such numbers are measured in radians per unit time.
No issue if you haven't studied trig. ratios, just use AAA congruent property and pythagorean theorem. tada
Can you use Cosine to find the area of a triangle when two sides and an angle are given or do you just have to use sine rule everytime?
Depends on whether your two sides and an angle are SSA or SAS.
yea i mean u have to use cos rule here to find cb and then u can apply heron's formula
right?
or if u have calculator then you won't even have to use the rules
because you could just draw a line perpendicular to ab joined to c
then just using trig ratios u can add the areas of the 2 smaller triangles u have
Someone knows about vectors?
Sorry I was sleeping lol
I see, on the basic trigo identities tho, i just glimpsed a bit of it and realized that many of them were pretty much algebraic manipulation. Soon, I might see if memorizing it would be better or just some manipulation stuff would do
Iβm horrible at geometry help
the volume of a cylinder is unaffected by the lid right?
(3x + 48) + (x + 12) = 180
solve for x after that
since q and s are parralel these 2 angles are the same
actuallu an easier way to visualize it is
This might make it more intuitive
thanks alot
correction: AAA is not a congruence property. 2 triangles with the same angles "can" have different yet proportional corresponding side lengths
Aight when you're here ping me
e.g
Wut you doing
kinda here (I need to get ready for school(
huh?
Just ping me when you're here. Not kinda here
Uhh alr well I'll ping you in like 9 hours lol I got school
9 hours?
You're in a very bad timing conflict with me
Yeah school and possibly homework
Can someone please check what I have done wrong:
Extend DE and AB to meet at a common point Y. Now triangle ABC ~ triangle YBE
This gives BY/BE = 5/4 . Also triangle DBE ~ triangle BYE so BY/BE = DB/DE which leads to DE = 52/5 . So the ratio is 52/65
Can someone explain this, here the author is deriving 'law of cosines' but from what I see, shouldn't it be aβ’cos(theta) + b squared? Why is there a minus inbetween?
okay i am not that good at trig but i didnt understand how does the line that goes through D , that is parallel to AC meets cb
something i am missing ?
I didn't say it meets cb , I said extend AB
Oh you meant in the question
Why wouldn't it?
Erase the line be and de
And extend CB
oh i didnt know you can just extend it :D
<@&286206848099549185>
Lol I'm in American central standard time zone
Thx!
Is this PDF drunk? It says WX is a line, then goes on to say that 3 points make a plane as long as they aren't on the same line, so WXB is a plane?
Or am I misunderstanding something
Or am I to read that as the line doesn't exist when they are defining plane and to just consider the points WXB
Could someone please solve this problem?
Given a pyramid A-BCD, AB=CD=AC=BD=a. AD=BC=b, if A, B, C, D are all located on the surface of the same sphere with radius of 2, determine the range of a+b.
Anybody knows the proof to the fact that
If there's a circle C1 then when we drawn another circle C2 through 3 points:
A random point P outside C1,
Two points of contact of tangent from P onto the circle C1
then C2 also passed through centre of C1?
(I know Thales theorem but that doesn't prove this cause I don't know if there's only one such cases possible or multiple)
np
@woven shoal alright im here
To ask for mathematics help on this server, please open your own help channel or help thread. See #βhow-to-get-help for instructions.
\colorlet{a}{blue!40}
\colorlet{b}{red!40}
\begin{tikzpicture}[scale=3,c/.style={a},d/.style={b},column 1/.style={anchor=east},column 2/.style={anchor=west},row 4/.style={font=\Large},row 8/.style={font=\Large}]
\pgfmathsetmacro\aA{20}
\pgfmathsetmacro\aB{60}
\coordinatelabel=left:$O$at(0,0);
\coordinatelabel={[c]\aA:${C =(\cos A,\sin A)}$}at(\aA:1);
\coordinatelabel={[d]-\aB:${D =(\cos(-B),\sin(-B))}$}at(-\aB:1);
\coordinatelabel=right:$E$at(1,0);
\draw(O)circle(1);
\foreach\V\colo in{A/c,B/d,E/{}}{\draw->,\colo--(\V);}
\draw->,carc(0:\aA:0.3);
\draw->,darc(0:{-\aB}:0.25);
\node[c]at(\aA/2:.4){$A$};
\node[d]at(-\aB/2:.4){$-B$};
\node[sloped,above,c]at($(O)!.5!(A)$){$\vec{a}$};
\node[sloped,below,d]at($(O)!.5!(B)$){$\vec{b}$};
\matrix[matrix of math nodes,anchor=north]at(current bounding box.south){
{\color{a}\vec{a}}\times{\color{b}\vec{b}}&={\color{a}|\vec{a}|},{\color{b}|\vec{b}|}\sin((-{\color{a}A})+(-{\color{b}B}))\
({\color{a}\cos A}\hat{\bf i}+{\color{a}\sin A}\hat{\bf j})\times
({\color{b}\cos(-B)}\hat{\bf i}+{\color{b}\sin(-B)}\hat{\bf j})&=
({\color{a}1})({\color{b}1})(-\sin({\color{a}A}+{\color{b}B}))\hat{\bf k}\
\sin({\color{a}A}+{\color{b}B})&=-({\color{a}\cos A},{\color{b}\sin(-B)}-{\color{a}\sin A},{\color{b}\cos(-B)})\
\sin({\color{a}A}+{\color{b}B})&={\color{a}\cos A},{\color{b}\sin B}+{\color{a}\sin A},{\color{b}\cos B}\
{\color{a}\vec{a}}\cdot{\color{b}\vec{b}}&={\color{a}|\vec{a}|},{\color{b}|\vec{b}|}\cos((-{\color{a}A})+(-{\color{b}B}))\
({\color{a}\cos A}\hat{\bf i}+{\color{a}\sin A}\hat{\bf j})\cdot
({\color{b}\cos(-B)}\hat{\bf i}+{\color{b}\sin(-B)}\hat{\bf j})&=
({\color{a}1})({\color{b}1})(\cos({\color{a}A}+{\color{b}B}))\
\cos({\color{a}A}+{\color{b}B})&=({\color{a}\cos A},{\color{b}\cos(-B)}-{\color{a}\sin A},{\color{b}\sin(-B)})\
\cos({\color{a}A}+{\color{b}B})&={\color{a}\cos A},{\color{b}\cos B}-{\color{a}\sin A},{\color{b}\sin B}\
};
\end{tikzpicture}
vin100
hi
does anyone know how to solve this one??
<@&286206848099549185> ?
I can't think of a single start
!help
To ask for mathematics help on this server, please open your own help channel or help thread. See #βhow-to-get-help for instructions.
oh
what does this do?
read the message π
look
youre good π
Are you right now
I saw that circle kinda thing of yours so
Lol
yeah no thats super useful
I mean there should be others available online
wowie
Does anyone know what is Pythagoras related to real-life application
"phythagoras" and you are absolutely sure it starts with a ph and not just p?
anyway like
i guess the most "real world" that you're gonna get is calculating distances
in various circumstances
like... idk if you were designing a sloped roof on a house and you know how tall it is and how far it needs to extend horizontally
you are gonna need the theorem to calculate how much roofing you need
Anyway in graphic designer
Or geometry related
All 2D-based object triangles then combine two 90-degree triangles and here the box
...
So in this topic, I will guess the basics of all shapes is triangle
I want to be an architect btw
i gotta do something
Indeed. I discovered it in my programming language theories
A square is a combination of 2 triangles, a cube 2*6 = 12
A circle, many triangles
And even though, triangle is made of a single triangle (wow)
I have been working in this problem for some days and still don't have any solution.
It ask for the triangle with the biggest area that you can find with the vertices on the circumferences.
I had some ideias, like use the cosine law with the three central angles, what's a way to found the sides in function of the radius.
I don't have a full solution, but you'll want to have OA perpendicular to BC, OB perpendicular to AC, OC perpendicular to AB.
(If they're not, moving just one of the points so its radius becomes perpendicular to the opposite side will make the triangle larger).
Hmm, and we can then derive using the law of sines that the cosines of the three central angles stand in the same ratios as the three radii.
how do you plot by hand w(t)=.3125(1-cos(160t)/2) I have T=12.5 ms and the wave peaks at 312.5mW.
Hey can anyone help me with this, its angle relationships
SR?
Yeah
You're doing a test?
but Iβm not sure
Itβs not a test itβs a practice test for this week
Itβs worth 25 points
It's worth points in your Grade????
is this one correct? @woven shoal
Angle sum in a triangle.
Compute the inside angles first.
Then what
Once you know the inside angle next to the xΒ° you want to find, it is easy to get the last bit of the way.
Does "vertical angles" match something you've learned?
its like linear pair postulate
I think
!nosols
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.
And it's not the right answer anyway.
I know my hand writing sucks but am I right on this problem
tan(x-pi/4)+2
Also posted this in a help channel
In the right-angled triangle ABC with angle ABC = 90, let's denote by D the foot of the height from A and by M the middle of the leg AB. The bisector of angle ABC intersects the bisector of angle DAC at point E. Show that:
a. Triangle AME is isosceles
b. ME parallel to BC
Can someone help me on trig real quick
I can try if u give an example on what u are confused on or a question from hw
@stark vapor
like i'll draw one of these
and from it i can just start pulling identities out
i know how to create the identities from this circle at least lol
what identities, give me an example
sin x = sin (pi-x)
-sin x = sin -x
cos x + pi = -cos x
cos x = -cos (pi-x)
tan x+pi = tan x
tan (pi-x) = -tan x
and so on
ah
personally i just remember these:
sin(x + pi/2) = cos(x)
cos(x + pi/2) = -sin(x)
sin(-x) = -sin(x)
cos(-x) = cos(x)
and then tan = sin/cos
well imma take your word for it lol and just remember what i need
also i have sin^2+cos^2=1 already memorized along with the cofunction identities and yeah
it's just the symmetry identities or whatever they're called are a little tricky
but these are the most useful out of all of them i assume
yeah maybe also memorize cos(x + pi) = -cos x and sin(x + pi) = -sin x
oh yeah ofc
technically you can rederive it from sin(x + pi/2) and cos(x + pi/2) but itβs not hard to remember adding pi
then one has cos(pi - x) = -cos(-x) = -cos x
since cos(-x) = cos x
saying cos(2pi - x) = cos x is like, a geometric way to state it, too, but i prefer just saying cos(-x) = x
since cos(t + 2pi) = cos t for all t
yeah
cuz 2pi just returns you to the original spot so nothing really changed
being able to imagine the unit circle makes comprehending and memorizing all of this so much easier
thats why im always randomly constructing unit circles and writing literally all the information i see from that circle
to test myself to see how much i've memorized
and each time i do it i can write a little bit more on my paper so yeah thats fun
Point O is the center of the circle, point A is inside the circle, and point B is the outside point. OA=6.7 cm; OB=7.5 cm. Find the length of the radius of the circle if it is known to be expressed as an integer in centimeters
<@&286206848099549185>
Ang, QPR Is half QSR because inscribe angle is half of central angle standing om same arc
So
As QSR = 88Β° SO, QPR = 44Β°
bit confused with this one. i tried using the area=1/2absin(c) but got mixed up. help
Hi!
Use this Area=1/2 x r^2 (2ΟΞΈ/360ββsinΞΈ)
11m^2 = 1/2 x r^2 (2Ο(75)/360ββsinΞΈ)
This is the area of the minor segment
Once you have the radius, you might want to use the formula for the area of the triangle as 1/2 Γ r^2 Γ sinΞΈ
not sure ive learnt this sorry π₯²
What formula do you use?
1/2absin(c) is the Sine Area Rule
The area of the triangle is actually taken from the Sine area rule
nevermind i still havent got it. how should i go about solving for the radius
mhmm i tried that but i mightve done smth wrong because it didnt match the answer in the answers sheet
ill try again
give me the answer in the answer sheet
radius 8.008m, triangle 31.0m^2
Ok I'll check if it works
it probably does, thanks
Area=1/2 x r^2 (2ΟΞΈ/360ββsinΞΈ)
11m^2 = 1/2 x r^2 (2Ο(75)/360ββsin75)
11m^2 = 1/2 x r^2 (1.309 - 0.966)
11m^2 = 1/2 x r^2 (0.343)
11m^2 = 0.343r^2/2
11(2/0.343) = r^2
β64.14 = r^2
r = 8.008m
got it
ahh i see now
i was trying to use this rule to find the radius haha
use the formula for area of the triangle that I gave you. Might work.
there is no radius on your sine area rule
yup i kinda figured that out. i forgot the other rule u wrote existed
only started learning this today so im still trying to get my head around it

alrighty
i got it
30,97, rounded to 31.0
thanks a bunch :) couldnt have done this without your help
Good evening, sorry to bother you. What is the meaning of the double arrow? Does it mean the QS vector?
the line going through the points "Q" and "S"
Thank you I did not know this notation, is it the equivalent of the following image?
it is not. usually, that notation is used for vectors and rays depending on the context
Ray
Oh thank you for the explanations ^^
if it is AB with the arrow to the right, usually it is talking about a ray
costheta = -8/17 where pi/2 lessthan = to theta < pi
find tan2theta
I got 240/161
does that look correct?
can barely see the writing
I can see it
i can but it ain't clear
ahh
Hello is it correct to say that the curvature of a curve represents the difficulty of approximating this curve by a polynomial application?
most books have exercise questions
https://cdn.discordapp.com/attachments/801167302913032213/1120545784853700618/image.png?ex=65373095&is=6524bb95&hm=dcfc33cf88fdc0a1ce97999b93c9a9864dfa087f9876c5254797926705b7329b&
i forgot how to do this, can someone explain?
do you know similar triangles ?
Yeah but there are books with only practice questions
And then there are textbooks
With a mix of learning material pairs with examples and except uses
yeah is the equation like 11/4x = x+12
yeah can you solve it ? (x is to the numerator in 11/4x)
how would i solve it that way?
i can solve it 4/11x = x/x+12
Primordial
Primordial
which country's question is this
i anit even getting a clue
Hint: ||add two more triangles to make a square||
for the derivation of eqn of hyperbola why is b^2 = c^2-a^2? for ellipses theres a proper geometrical way to determine b^2 = a^2-c^2 but i cannot find why this equation holds for hyperbolas
i saw a video and it said that b^2 = c^2-a^2 is just an arbituary constant thats meant to represent c^2-a^2 after deriving the formula to x^2/a^2 - y^2/c^2-a^2 = 1
??
Hi
Welcome π
I'm taking trig rn, started graphing and... proofs
do you have more recaptcha puzzles
Where did you find them though? It was a long time ago
Did you really dig through the entire server?
there exists no x:|x| = x ?
It was a trick question, try again
π’
hint: ||There are 2 false statements||

Yeah, that was an error on my side, but I turned it into a mechanic now
i think all are correct
Statement 2 and 4
Assuming a, b, and c isn't restricted in positive numbers
Actually statement 1 too
think about 0,5^2
ah right
oh
How could I not think of this
yesterday my teacher asked me to prove that a triangle is a triangle and i said because it has three sides
is there any other reaoson why tho
show your diagram.
I can't understand, what differences do I have to make when graphing tangent? I can graph sin and cos kind of well
Tangent is just fundamentally different
Drawing a bunch of lines as borders starting at pi/2 and repeating in both directions every pi
Then just draw a weird cubic shaped graph between then
This sounds silly and I'm probably on the wrong discord server for this, but I'm making a minigame and I want to figure out how to detect if a player is looking at another player based on their yaw & pitch.
For example, I'm staring at this NPC named "Aryn":
https://media.essential.gg/933f89d0-9cf2-49b3-ce6f-adfe3f60ba00
And as you can see Minecraft says my yaw value is 63 & pitch value being 1 (as you can see top left).
Minecraft also has boundaries and limitations on their yaw value when it hits a value of 180, where it becomes -180, same when it crosses 0 (1, to 0, to -1) afterwards. If anyone who plays Minecraft can denote a connection between this reasoning and the real life applications of trigonometry then please help me figure this one out.
tl;dr I know trigonometry is involved so if anyone can tell me how I could use that here that would be awesome thank you
help me figure out how to detect if a player is looking at another player using yaw & pitch coordinates
What coordinate axes does yaw work with? (e.g. looking straight at positive x axis is a yaw of 90)
Either way, for the yaw, imagine drawing a graph of minecraft x and z (east-west and north-south respectively) coordinates. The two players will be two points on those axes, and the yaw will tell you which way one of those players is looking. To check that a player is looking in the direction of another player, you can use an inverse trig function, using the distances between the two players in the x and z axis, to check if the angle between the two players matches the yaw.
For the pitch, imagine a graph of distance between the players-height of players. Using that, you can again use an inverse trig function to see if the angle between the two players matches the pitch.
@gilded dew , does that help you?
Sort of, im using ChatGPT to actually help me and he's helped me a lot
Apparently something to do with the dot product formula
Thanks though, I think my work here is done
chatgpt can't do math
if you are looking for all triplets of integers which form the sides of a right triangle, it is infinite and has well-known characterizations: https://en.wikipedia.org/wiki/Pythagorean_triple#:~:text=68%2C 285%2C 293)-,Generating%20a%20triple,-%5Bedit%5D
if I dervied a formula from something (e.g property, equations, etc), can it also be a proof to why the formula works?
i.e can it be like proving the formula itself
Youβd be surprised
Nah chatgpt gave me the dot formula and convert pitches and yaw values in Minecraft to their respective unit vectors
gpt 4?
It even changed the calculations for arctan based on how Minecraft interprets the yaw range of values
idk but I just used a free version
free version is shit at math
they once gave me chatgpt plus for three months and still found it shit at math
Ok
before it goes away they added a image feature
what?
i got a queston
guys
can u help me
so when ur trying to prove that 2 triangles are congruent
like triangle ABC and triangle DEC
u use statement and reason format right?
im pretty new to geometry so im kind of confused
right
did u get it?
LMAOOO no sorry
anyone know how to graph trig functions? I'm stuck
Guys my Yankee ahh teacher asking me what a 1M sided shape is named? I Googled BU nun came up
By shape I mean polygon pentagon yk
almost a circle
bruh why does this even exist its basically a circle
u cant even see any of the sides lmao
,rotate
I got an answer through brute force but I'm not sure how to do it normally
I got 8cmΒ² which is right but I kinds guessed
Cus what if EB was triple AD or if DF was not half of AD?
Am I meant to guess?
@empty tiger
Can i give you my answer ?
Sure
Same as saying 8/4 =4/DF
I think the values I said were wrong
The values you said were right
I don't think EB = 8
But your answer was wrong because you didn't justify
If the longer side to smaller side = 5:2 then I gotta do 4/2.5, no?
To work out DF?
The ratio is 10:4
Which is 5:2
Yes
So if the 4cm is the 5 in the 5:2 then surely the 2 is 4/2.5?
I may have confused you with my original values I wrote on
U were right
That's it
Hm
I feel like I'm asking too many questions on this test but the main reason I'm doing it is to see my weak points
Anyway if you have anything else to ask...
'rotate
Love the scale of the rectangles
I'm so lost on this one ngel
,rotate
I don't know where to start, because in my mind I'm blank because I don't know the shape
Wow i'm trying to figure out what that means cuz im not an english guy and that's blank to me
I can help? What terms don't make sense?
Surface area
The area of the each sides face added up
So like on a cube you'd do the area of each square and add them up
Google would probably help more than me
The surface can be converted Into a square
Wdym?
I'm so confused, I think I'm better off asking my teacher, but I won't be able to sleep without knowing. Can I come back to you in like 20 mins?
hey
I just found out the SA of a cube of V=8 is the same as the SA of a sphère of V=8
Volume
i dont think it is
I just did it by hand
2x2x6=24 for dube
ratio of areas: 4 to 9
ratio of sides: 2 to 3
ratio of volumes: 8 to 27
405/27*8 = 120
Just destroyed my whole research 'bout that to demonstrate it
also is that edexcel gcse maths?
2015, yes
nice, i remember doing gcse a loong time ago. back when maths was way easier
What is it ?
that is so much simpler than i anticid lmao
exams when youre 16
vector 5 markers?
I know this isnt the case but surely this only works for squares? (Someone else can snwer for them)
Well since all shapes can be converted Into cubes, this do works
For 3d shapes
And since 2d shapes can be turned Into squares it works too
i dont unserstand
Imagine you have a sphere with a volume of 8 cm^3
This is the same as saying you have a cube with a volume of 8 cm^3
Volumes stay thΓ© same not the solids
That's topology
I can't explain very further
I just fried to prove you wronwrong and instead proved you right, which js good
That's the same as having a ball with a non-stretchable surface, you Can bend it and change its shape but thΓ© volume and thΓ© surface area will stay thΓ© same
Eventualy you Can bend your ball so that it becomes a cube
Here you are !π
Can i add you as a friend so that if we have more things to talk about we Can ?
sure!
Nice
Can someone help me with a problem
Im confused how to solve for X
Nevermind I found it out
X=29
Akira
Send help
can someone solve this for me ive been waiting for like for over an hour
Add the equations together
with like terms
"Send help" is an interesting way of saying it lol
Is this correct??
should be because all interior angles add up to 180
u can always check by using an exterior angle as well
what the hell of a diagram is that
Idk how to find angle DAB PLS HELP
geometry dash
first of all, you must understand that KM is a line bisector of JL and angle bisector of JKL. therefore, angle JKM and angle LKM are congruent. Therefore, using SAS theorem, we can conclude that both triangles are congruent. Therefore, line JM is equal to line ML, so 3x + 4 = 5x - 16. Using algebra,
3x + 4 = 5x - 16
3x - 5x + 4 = -16
-2x + 4 = -16
-2x = -20
x = 10
Therefore, since JL = JM + ML
3x + 4 + 5x - 16
3x + 5x + 4 - 16
8x - 12
8(10)-12
80-12
68
of course, always recheck my work because i may have made a few mistakes
im doing this all in my head so theres a high chance there might be a few mistakes
how are 5 and 8 congruent
,rotate
youre welcome
what
no i was talking to the people that are going to try to answer the qudstion
i hate geometry so im not even going to try but i rotated it so its easier to read for those people whoo are going to answer
oh alr
my brain isnt working what
the 3rd one right
bcs if its equilateral its gonna be acute as well bcs 60 degree angles
rights can be scalene if u just increase the lenghts
and iscoseles can be obtuse obviously
Da 3rd one coz an equilateral triangle must have three same angles of 60 degrees so it cant be obtuse
3
is it any special kind of special quadrilateral or not
cuz obviously you canβt say that with 0 information
need more info, only way I can think of that happening is EBDC is a parallelogram, which basically means that all those triangles are equilateral
Perhaps the question mentions 2ED = AC and the perpendicular line from point B to ED bisects ED?
and ACDE is a trapezium
has anyone got deductive gemoetry like provin congruency and similarity worksheets and resources i can find
would be rlly helpful
Hello fellow trigonometricians
what about geometricians
ye
Good as the old days (From the last 3000 years literally)
You can refer "A School Geometry" by Hall and Stevens
For a bit hard, Challenge and Thrill of Pre-College Mathematics
Both the books are available free online
A School geometry is very easy and gives you some good practice while challenge and thrill of pre-college mathematics very good problems on similarity and congruency
poor helper getting pinged for no reason 
fr
imagine a triangle whose each interior angle is >90 deg when triangles have total of 180 interior angle deg.
Could anyone help with this. circle theorems and you need to find x and y, anwsee in cm
i forgot particular theorems but the way I see it is like this
then u can find the hypotenuse i.e the red line, thus x and y
Yep thank you
Hi I have a problem, can someone tell me why if I have an equation sinx + cosx = 1 why can't I just square both sides
Bc when I do it I'm getting wrong results and idk why
I don't understand why the solution of sin(x) = -(sqrt(3)/2)
is -2pi/3
I made a post about it here: #1164248299197431808
a' is the new point and if a is going there then everything else also has to do the same thing, meaning u literally move all the points 5 units to the left
and thats quadrilateral a'b'c'd'
oh wait
u need to rotate it first
90 degree clockwise is gonna be a at (-1, 1), b at (-3, 1), c at (-4, 4), and d at (-2, 4)
abd then u move it all 2 units up and 5 units to the left
yes equilateral triangles always have three 60 degree angles
three
Help pls π’
do you know the properties of a circumcenter?
if u do, you can very easily solve 3 and 4 with no math at all
not even a. single expression or equation is needed
point P is the incenter for problem 5 and 6
knowing the properties of an incenter will have you easily solve the next 2
power of AI 
are u supposed to solve for x or what? @snow crystal
Yes
But When I square both sides I dont get the correct result
Are u informed of the coorect answers though?
@snow crystal
Anyways
- sqaure both sides
- use the identity sin^2 (A) + cos^2 (A) = 1
- u will get an equation containing sinA Γ cosA in the left side and 0 in the right
- if sinA = 0, A =?
- if cosA = 0, A =?
Hence A =..
Please anyone help f(x) = 4^x
what is the full question
thatβs just an exponential function?
Yes it is
so what do u need help with
Graph and solutions on how to solve it

