#geometry-and-trigonometry
1 messages · Page 3 of 1
yea thats why i wrote it
Anyone has a lead?
hi im a newbie here and i wanna get help on my calculus subject
is the someone who knows about discontinuties?
Go to help section.
Hello fellow mates, I’m back
I don’t seem to get what should I even begin with
If someone can help me understand such questions, I’ll be in debt forever to them
what have you tried?
do you have a compass and straight edge?
(note that did not use ruler as you're not supposed to measure distance with that)
ofc ofc
anyway start with a single point
just make a single point?
for now yes
use the compass to copy the length of one of the long segments
once you have the arms at the correct length, then you draw in your arc
centred at the point I initially told you to draw
small indicator
done
clear enough to be seen and able to draw a line from your point to it
ofc
same idea of copying length to get point E
arc on E?
wdym
you copy the appropriate length
make an arc that intersects with your first line and if you did that properly, the intersection will be E
How do you find out which points in a polygon (which points make the polygon concave)
what
i started with A
found C
small arc on C
yes
how are you getting E over there
E isn't just anywhere between A and C
oh sorry
it's at a specific location
i'm using like a seperate piece of paper with different lines
you have to copy the diagram exactly
i just need to know how to like solve these things though
so you E needs to be in the same relative position from the A and C in the original
you can't just place it anywhere you want
just like how you couldn't make AC any length you want
i understand that
and why I specifically told you to use the compass to copy length
copy the length AE
tbf i also did say this and that my goal was figure out how to solve these
but i'll do it exactly sure
make it easier for both of us
I'm giving relatively simple instructions
did you copy the length just like you did with AC earlier?
tbf i also did say this and that my goal was figure out how to solve these
for this it's pretty much copying lengths and finding intersections
that looks a lot more reasonable
now consider
AB and EB
copy the appropriate lengths, make two arcs and find where they intersect to get B
how do i like get the proper angle though
ab and eb are on different lines, but like how do i place B properly to get the same angle
and not possible with the allowed tools
i need to make a copy of the image with 5 arcs and 2 lines
i don’t think i said there were any tool restrictions
compass and straight edge only is implied
note that B is a certain distance from A, same idea for E
considering the distance from A to B
drawing an arc with that distance from A, gives the potential location of B
doing the same for E, and BE gives you another arc
the intersection of these two arcs will be the location of B
full circle on A?
yes
and do i continue the arc from E to a full circle to find D?
considering you know the general location of D, again full circle isn't needed
measure ED, and a decent size arc at the top right is enough
you are not told whether EB is the same as ED nor should you assume that if that's what you were planning
is this the final product
yeh
well technically your line shouldnt extend past the arc at D
the arc is there to tell you where to stop
linear line?
ok thx so muchhhhhhh
trigonometry? CRINGE draw me some axels brutha
sheesh
how would you write the answer to this question?
hey y’all I need help
It depends on how you answered it. If you're asking how to solve it, then use the property that two parallel lines form the same angles when a 3rd line intersects them. And that sum of the angles formed is 180 degrees. What do you get when you sum m∠1 and m∠2?
Yep, sorry
Wdym sub in the 60?
substitute
you're trying to find out what happens when theta is 60°
so it would make sense to replace those theta with 60°
after subbing in 60 and doing a small step in simplification
ℝamonov
similar idea for $cos^2(30\deg) = (\cos(30\deg))^2$
ℝamonov
yuo shouldn't be cubing or squaring 30 itself
Oh okay
=0.19245009
=0.19245009*4
=0.769800359
=0.769800359/3
=0.25660012
you should be working with exact values
What's that supposed to mean?
no decimal appriximations
you dont
use a calculator
these are special angles and you should know the exact value of trig functions at these angles
Sorry, I'm not quite getting you
without using a calculator, tan(30°) = ?
0.5 sum sum?
Not sure if I was taught that yet 😅
Have you learned the unit circle @magic otter?
Nope
What do they expect from you? The answer simplified to cosine and sine? A decimal approximation? An exact result in radians?
so yeh, exact values
That's the answers from the textbook 🤷♂️
look up special trig ratios
Looking at it
Ohh I see!
It
It's getting late, I think I'm gonna head to bed
Thanks for the help!
Let α be an acute angle measured in radians. Prove the
inequality cos α > 1 − α
A geometric proof:
cos (-1 rad) = 0.54030230586 < 1 - (-1) = 2
ig its wrong
idk
Hey guys, does the drawn shape makes sense?
i am not sure but i dont think a trapezium can have opposite angle 90
If anything, it should be a rectangle right? But the measures would be off
yea
Let α be an acute angle measured in radians. Prove the
inequality cos α > 1 − α^2
i missed ^2
If anything, it should be a rectangle right? But the measures would be off
refer to my less confusing diagram
its not supposed to be a rectangle
So you suggest it is a trapezoid?
but opposite angle cant be 90 in a quadrilateral it has to be 90
wdym
angle A = angle C =90
is that even possible
its a better scale than the one provided
yea but is it possible
and if you've done circle geo before, you'd know this is possible
isnt this the only kind of it possible
no
and if you've done circle geo before, you'd know this is possible
from thales theorem
do you have any article i can refer to
thales circle theorem
ok
thnx
oh thales circle theorem is one in which angle formed on one side of semi circle is 90
ik that
never thought it would apply here
thnx for telling
non linear 
Anyone know how to apply to be a mod
Alright
help numerous of people in math (as much as subjects as possible) and then request for mod
or just dance in the air. LOAOOAOAOOAOAOAL
Haha
Well ask me for help if you need it then
And thanks
hey y'all, just a dumb no math game dev over here. I'm trying to figure out how to get the arc of the circle that is inside of this triangle. I need the angle of the overlapping arc of the circle that's inside of the red circle in the illustration. Anyone got any ideas?
Only 5 periodic patterns right?
And they can be gotten from one side of platonic shapes right?
,w arcsin(1)
why does this give 90 only
why not 450
or other angles with sin as 1
because arcsin(x) is the angle between -90° and 90° whose sine is x
such is its definition
thnx
how can I simplify $cos^{2} x$
mstf
You can't rlly simplify it, but you can rewrite it in alternate forms such as $1-\sin^2 x$ and $\frac{\cos 2x+1}{2}$ if you want.
enclave wangedrocht
thanks
have no idea what to do or where to start
im confused how to do that
how do i find BC
so since a^2 + b^2 = c^2, rearrange this to find length of BC and it becomes 11^2 - 8^2 = b^2
ohh ok
so then what do i do after that??
i got 57
but i dk what to do next
square root 57??
which rounds to 7.55
yes, √ this is the symbol for square root
have you learned sohcahtoa?
yeh
so which one do you think we should use, sin, cos, or tan?
with the length BC in our hands
tan maybe??
correct! good job
because you want to find BD which is adjacent, and tan is opposite over adjacent
so tan(28) = 7.55/BD
Rearange this to find length of BD
im stuck on the rearranging part 😭
i’m kinda getting it but i’m stuck how to do this
np!
okay from pythagorean theorem we see that BC^2 = AC^2 - AB^2
so we have BC^2 = (11.2)^2-(8.7)^2
,w sqrt((11.2)^2 -(8.7)^2)
so we get BC=7.05
tyy
do you get it?
yh
and next for angle we can use sin(x)=oppo/hypo
hypotenuse is 3 the y angle is 65 the x angle is 25 i have no idea how to do this can someone teach me from beginning
sin(25) = y/3
sin(65) = x/3
you're given a lot of information, so can do it a few ways. do you have the original problem?
well, do you know the trig identities?
no
you know what sin, cos, and tan represent on that triangle?
tangent
is
both corners
sine is
bottom
and
cosine is top
right
or is it the other way around
soh, cah, toa.
sine = opposite/hypotenuse
cosine = adjacent/hypotenuse
tangent = opposite/adjacent
close
the opposite is the side of the triangle that is 'opposite' the angle. it doesn't make an angle with it
im very close
do you know what to do now?
@upper karma use sentences. you can use commas instead of new lines to represent pauses in speech
the sine, cosine, and tangent represent different ratios of sides in a right angle triangle.
sine 25 /65 *3
can you identify the opposite, adjacent, and hypotenuse in your triangle?
sin(25) = opp/hyp
do not confuse angles with sides
yes
Can someone help me?
assume yes next time you ask, and just send the problem.
they tell you that the sides AB and BC are the same length. this means that the triangle can be split into two equal right angle triangle. the symmetry of which gives you the angle BCA
Do you get how <BCA is 71 also
from here, you should be able to get BCD by using one other property
Is it possible to find the orange and yellow angle with the information given? Ive tried help with no luck someone suggested to try here.
There is a help section above but ill give it my best college try.
Add $2sin^2y$ to both sides to get: $cos^2y+sin^2y = 1$
NotMyself
And thats an identity
Thanksssssssss
Consider the quadrilateral to the left of the red line with the orange angle.
The sum of the corner angles are (53°+53°)+(53°+53°)+orange+orange.
But the angle sum in a quadrilateral is always 360°, so you get an equation that you can solve for 'orange', getting 74°.
(concluding that the joint between the 76° and 80° angles will not be exactly parallel to the ends, but must be an aesthetic compromise between "bisect the overall angle" and "don't point too much forwards").
I dont know exactly what you said if there is something specific I could lookup to read so that going forward I could solve this myself I would appreciate it. If you know red that would also be awesome
Hmm, the most general property I used was that the sum of the corner angles in an n-gon is (n-2)·180°.
That the two corner angles at the head end are 53°+53° each is something I concluded by looking at the drawing and wondering what exactly the 53° numbers referred to.
So would yellow be 82? Meaning an 8 degree cut?
Or did I derp your math?
Yes, I would get 82°. I'm not sure exactly what it is you would cut at 8°, though.
The end of the wood to fit in there as a shelf
Ah, okay.
Cant tell you how big of a help that was
So when I go make my cuts w.e length I want the shelf to be (depends on where inside I want them to fit) I know I have to cut the angles at the end to 16 for a top fit and 8 to fit in that bottom portion.
It might be easier in practice to measure the total length each side of the shelf, and transfer that to each side of the board, rather than measuring angles.
Would that somehow help me get the angles faster/easier that I need so they drop in?
If you're using a cutting tool that that you need a numeric angle to set to, then go on and start with the angles.
I was imagining you needed to draw a physical line on the board to cut along.
Yeah I need to set it at an angle for as flush of a fit as possible.
That might make a little more sense to you its a bit beyond me
Stuff like that. Just a hobby im getting into.
hi
I love geometry 🥰
SOMEONE ON EARTH PLEASE SOLVE THIS PROBLEM
if you love,you will try to solve this problem
I love geometry I’m not this good at it lol
xD okay
I would have to draw it out to even get a visual
What are you struggling with though
everything
Try drawing it
just draw it and send me
😄 😄
I can’t do all your work for you
OKAY 🙂 😄
Ok so im taking geometry in 8th grade and my teacher gave us extra credit that no one in my class can do, and my parents can’t either. Would someone pls be willing to try and help me
I’ve tried for hours to do it
Pls help
have you drawn it?
Ooh this is fun it’s not geometry though it’s logic
I forgot will do it right now
I will try to do them both
I’ve drawn it but it is kind of complicated
Do you know what a circumcircle is? Try drawing it yourself and figuring it out
Working on this too. The hard part is that you have so much information you need to figure out a good way to visualize it
Yea
It would take too much time I am not sure
I did a similar problem before but it was much easier this one has so much going on because it’s mostly about characteristics they don’t share instead of what they do share
Which means you have to use process of elimination
If you really want to solve it write out each of the 20 things with a massive amount of space
Then write out the other 19 things across from the one you already wrote
And draw the relationship between each
It takes up so much space and it would be really time consuming
Ok thanks
It prob wouldn’t be longer then 6 hours lol
Im not really sure where to go with this but I need help with a vector problem
Less than 2
Probably
Ok
I think it is the most certain method
I have:
||James / Babalu / CONTROL / K.K.K.K.K||
||Mata / Hero / KAOS / I.I.I.I.I||
||Boris / Fox / Spies / C.C.C.C.||
||Matt / Dimples / Master Spies / S.S.S.S.||
||Natasha / Fearless / Intelligence / M.M.M.M.||
I think that's enough now.
Ight
@quasi furnace do you still need help?
hi have you drawn problem?
Yeah but I don’t think it will help you much
is there more context
at its current state
there are many solutions
oh wait
nvm
wait yeah
OH WAIT
i think it could be arcs
on a circle
other than that idk
Nope
Dude im a freshman and I dont know anything, a little help here??
lol alr
you know that the angles in a triangle add up to 180 degrees, yes?
What is the question? Find x?
yeah ik that but like-
...yes? is there an issue?
yeah idk how to put the equation correctly
well what symbol do we use for addition?
add all the angles and equate them to 180
ok so i have 2x - 5 degrees x+ 25 degrees and i have 2x -5 = 80 is that correct?
You missed the x and ur equation is wrong
there are 3 angles in triangle
Just add them
oh-
sounds like you overthought things
yeah im doing algebra 2 and gemetry at the same time so im getting confuesd
did i do it right this time
😭
you're overthinking it again and also you're still missing the plus signs at the bottom and the =180 at the top
ok so you're asked to find the value of this given theta = 30°
Mhm
so $\frac{4}{5} \cos^3(60^\circ)$
Ann
assuming i've read your low-res screenshot correctly
well do you know what cos(60°) is
yea 1/2
and can you tell me what (1/2)^3 is?
0.125
ew decimals
1/8
no you're overthinking this again
cos^3(x) just stands for [cos(x)]^3 !!
and you've already told me that cos^3(60°) = 1/8 !!!
you don't need to reintroduce another cos in there!
my equation was (6x+14) + (4x-8) + (2x+18) =180
ok well you did not write it clearly in the pic :p
the equation as you wrote just now is correct
ok so when i do my test tmmr i should get the triangles right atleast
hello yes so i have two erroneous proofs for the volume of a cone, i would like to know where the mistakes in the proofs are, and how they are related to correct methods of volume finding
first proof: volume of cone is $\pi h r^2$: cone is just a bunch of right triangles whose right angle vertex is the center of the base of the cone, each of these right triangles have area $\frac{1}{2}hr$, the circumference of the base is $2 \pi r$, since there is one of these right triangles for each point on the circumference of the base, the volume of the cone is $\pi h r^2$
alshfik
Someone else helped, so I deleted it! :D
Could I get some help on this?
I got 1.7 repeating
NotMyself
You just have to plug the value of theta and solve it
Hi I’m an artist learning how to do isometric/diametric pixel art. I have been struggling to understand how to make a perfect cube in this perspective though.
I was hoping someone could help me understand, or hand me an equation that can help me with this.
I need to be able to determine the width of the cube from a decided height and vice-versa.
Another artist tried to help me with an image and a short explanation but unfortunately I’m pretty bad at math and couldn’t figure it out. I can quote what they said if it helps explain what I’m trying to do.
Also I hope this is the right channel. Sorry if not ^^;
Here is what the other artist had to say “Here's a chart of a unit cube (i.e. a cube where all sides are 1 unit long) in common game projections, the last one on the bottom right is the relevant one here.
Notice how each side is 1/sqrt(2) or about 0.707 wide once projected, and the height is cos(arctan (1/2)) if you want strict pixel iso.
This means if your cube is 32px tall, each side should be about 25-26px wide. Or if you want each side to be 32px wide, then the cube should be about 39-40px tall. (The cube's height in this case is the height of the vertical edges of the cube, not the size of your image.)”
I’m not sure exactly how he uses the numbers to get the pixel counts
second proof: volume of cone is $\frac{1}{2} \pi h r^2$: make a cylinder with the same height as the cone and overlay them so their center lines are the same, now consider the intersection of some plane with the center line of the figures, the cross-section of the cylinder will be a rectangle and the cross-section of the cone will be a triangle which takes up one half of the square, since the formula for the volume of a cylinder is $\pi h r^2$, the volume of the cone is $\frac{1}{2} \pi h r^2$
The same way volume of a cylinder isn't equal to $rh\cdot 2\pi r = 2\pi r^2$
NotMyself
ty <3
what about the second nonproof?
idk thats above my level
a somewhat intuitive explanation would be that the outer regions of cross sections account for more of the volume than the inner ones
in fact, the proportion of the volume that the area accounts for is proportional to the distance of that area from the center line
Could some1 help me with this? It seems simple compared to the stuff that is asked here but I still need help, I know how the triangle looks + the angles but don't know how to solve it: A 100 meter high mast stands on the top of a mountain.
The base and the top of the mast are seen from a
observation point P of the valley at elevation angles α = 11.3° and β = 12.4°.
How high is the top of the mountain above the observation point?
Solution is: 996,88 m
you would need calculator for this
since its right angle
are you sure that β is the angle between the two diagonal lines?
From what I believe the elevation angle refers specifically to the angle from the horizontal (the ground)
I'm not sure tbh, I think you are right
nice, is there an example with simpler figures that makes this effect obvious?
yea ig they are right bcoz your question says angle of elevation beta
So first of all u should label the triangle so ts easy to calculate stuff
I think I misread your message but I ended up drawing a scuffed figure
the cross sectional areas (as highlighted in orange) of the two rings are the same but it is visually clear that the bottom one has a larger volume
ty <3
and since the cross sectional area of the cone is concentrated toward the center compared to the cylinder, you would rationally guess that the cone's colume is less than 1/2 of that of the cylinder (which is in fact true)
the method used in the first nonproof only works if the circumference of the circle you want to multiply the area of the 2d figure by is intersecting the 2d figure at its center of mass?
wdym lol
sorry for low hp image
that was from the quora link other dude sent
this smaller circle intersects the right triangle at its center of mass
woah :0
i never thought about it
is this the key property that allows the calculation to work?
probably (and you can give a proof with calculus and whatnot)
calculus isnt real 😤
do you still need help with the problem?
sort of, idk how to solve it in the end
yeea
ok so
i drew it again to make things a bit easier to look at
our goal is to find h
yas
do you know about trigonometric ratios?
yes
so basically the idea is to convert the angle information (you know the angles alpha and beta) into length information (you want to find out h and d)
so you should try to express the ratio of lengths in terms of trig functions (sin, cos, tan) of the angles given
so tan alpha = h / d , then tan beta = h+100/d ?
ye ye
with a calculator
oh
i dont think anyone is expected to do this without a calculator xd
you cant use a calculator for any exam in my school they just give us the values
oh thats weird
its common practice in my whole country lol
so the two equations an actually be converted to a system of linear equations in d and h
@nocturne remnant thank you btw
yea ig but you can make a right-angle triangle and then
@gilded thunder
eh might still need help after converting them lul
its just basic calculation after that
ok :3 so there is a general method when you have two linear equations and two unknowns (i underlined the unknowns in blue and the known constants in red*)
in this case you only want to solve for h so there are two steps
- write d in terms of h in one of the equations
- substitute that into the other equation (which converts it into a linear equation in h only)
How do you tell the difference between a sin and a cos function on a graph if they're shifted left/right? Couldn't it be either one?
yes, it could be either
Why is the area above the same size as the area below?
The red straight lines are parallel to each other, as are the green ones.
F and G are midpoints of the respective stretches.
Is there a name for this kind of pentagon?
The square and the triangle of this pentagon have the same size.
I know 3 is true but how do I explain it?
when stating that two polygons are congruent, you list the vertices of each in such a way that they correspond to each other
e.g. in the statement as written you would expect angle A = angle P, angle B = angle Q, CD = RS, etc.
Ty
Looks like this got ignored. Still need help if anyone is willing ^^;
The diagram at the bottom is not a true isometric projection, but an approximation to it which works better with the classic "mode 13" aesthetic. The slanted lines have a slope of exactly 1:2 (two pixels out, one pixel up/down), which give them a slope of 26.6° to the horizontal, where exact isometric would have 30°.
The numbers basically say that the height of a one-unit vertical should be about 0.866/0.707 = 1.225 times the pixel distance between adjacent verticals.
This means if your cube is 32px tall, each side should be about 25-26px wide
Note that 32 is about 1.225 × 26
Or if you want each side to be 32px wide, then the cube should be about 39-40px tall
1.225 × 32 = 39.2
In fact, I'm not convinced by the calculations in the diagram -- it looks to me like they give too tall verticals for the slant angle.
So far I have asked 3 different people and gotten 3 different answers. I’m super appreciative of the help though
Would it be correct if you swapped 0.866 for cos(arctan(1/2)) ?
Hmm, cos(arctan ½) is 0.894, which would make the verticals even taller, so my gut says no. I haven't done my own calculations yet, though. Stand by.
Alright thank you for your time ^^
Troposphere do you only use this channel for Pre-University?
I'm not sure I understand that question. Me personally or the general "you"?
I mean, can i only use this channel for pre university level
sorry my english isnt the best
Are you looking at a university-level geometry problem?
Nope
Everything within the broad topic is good for the channel. The "pre-university" categorization is more an approximate help for finding the channel you want; it doesn't restrict what can be talked about in it.
oh ok thank you :)
I do need help on something though with Geometry
Im just confused on what i should put next for the rest of the lines
This looks like the abomination the Americans call "high-school geometry" which would definitely be pre-university (that is, "earlier than the university level"). I don't know enough about its conventions to be of any help (but as far as I can even decode the problem, they must be looking for an acceptable way to say, "duh, the angles are equal because you just told me that each of them is 90°!").
prove the angles are right cause perpendicular lines then prove that the angles are congruent because all right angles are the same
After doing some diagrams of my own, I've concluded that I agree with the one you showed -- and in particular with the 0.866.
I think many games of the relevant era that tried to be isometric actually used a 1:1 ratio between horizontal and vertical (which squishes the picture vertically but on the other hand stays true to the property of true isometric that the far corner of the cube would be shown exactly behind the near one). So you may want to reduce the mathematically well motivated 1.225 ratio to something closer to 1, to stay closer to tradition -- but whether you do that, and by how much, will be an artistic choice, not a mathematical one.
So even if it looks a bit odd the diagram is correct?
Thank you so much for all the help. I greatly appreciate it c:
Yeah, it seems mathematically correct (except for the mislabeling as "isometric"; a true isometric projection would have α = arctan(1/sqrt2) = 35.3°, rather than the 30° that gives a nice 1:2 pixel slant).
Personally I'd shrink the verticals a bit and call it artistic freedom, but that's just me :-)
There is a 1 pixel arbitrariness in the height because of the way it tiles, so I will make it 1 pixel short. Tysvm
Need some help w this plz
does anyone know what simplest exact form means by chance?
Option D is correct because there are some property to prove congruency which are side angle side, angle side angle, side side side and if we choose option D, it is fulfilling the side angle side property and one side is common in both triangles
can anypne help
i don't think this is appropriate for #geometry-and-trigonometry
if you want i may be able to help in #proofs-and-logic
How to find the x using sin and cos theorema
Can you guys give me some feedback on this solution of mine? Like how clear are the writing, the explanations, the English, the diagrams, anything really.
two chords intersect in the interior of a circle such that the first chord is divided by the second into segments of length 8 and length 9 and the second chord is divided by the first into segments of length 3 and length x. find x
is there a non-analytic solution?
got a diagram for that?
What exactly you mean
You can use isosceles trapezoid properties
More specifically, that isosceles trapezoids are made from two congruent triangles and a rectangle
already solved
Sorry to bug you again. But for. 1:1 isometric, when you say move 1.225 closer to 1. is the ratio exactly 1?
Being able to tell what is a cube in both perspectives will help me decide on how best to use artistic liberty
It's exactly 1, but we need to be clear on what it is that exact number achieves.
In this figure, B is a mathematically ideal isometric projection of a wireframe cube. Note that all edges are exactly equally long on the figure; the sloping lines are at a 30° angle to horizontal. The hallmark of an isometric projection is that we see the far corner of the cube exactly behind the near one. But the cost of that is that the 30° angle doesn't really make a pretty straight line when pixellated.
A and C are different strategies for making the lines slope at 26.6° instead, for a nice pixellated 2:1 slope.
Drawing C does the mathematically nice thing and "moves the camera closer to the ground", just enough that the bottom and top edges of the cube become a bit flatter. This is a geometrically exact ("orthographic") perspective, just with a different camera angle than the isometric one. It has a height:width ratio of 1.225.
Drawing A instead simply squishes the entire diagram from B vertically, to a height:width ratio of 1. This preserves the "far corner right behind the near one" property, but looks visibly distorted -- it is not the correct perspective from any viewpoint. Its main virtue is that it simplifies the coordinate calculations for games that need to represent a 3D game world using low-resolution 2D assets.
Then again, even though I know drawing C shows a correctly calculated perspective, my brain still thinks it shows a block that is slightly taller than it is wide. My reason for making the verticals a bit shorter would be to counter that illusion, but making them as short as A is definitely too much for my taste.
Thank you c:
use solution of a right triangle (when 1 side and 1 angle values are given) where cos theta = x/given side
How can I get coordinates out of wolfram? I'm trying to get the line "x=1-2r y=2+3r z=3-r"
define "get coordinates"?
Just draw the line on a coordinates map
Hey I'm a highschool freshman and is going to take the SAT in my sophomore year. My school wont let me take trigonometry can anyone help me learn trig?
What's your rush?
khan acad
where did you get this task from?
It was posted in #competition-math earlier, but @vernal cloak didn't respond to the comments it got there.
Maybe no one tagged me. Sorry about that i dont use discord at all, except using this server
Some math channel on telegram
nice name
yaya got it thanksss
The last time I've done Trigo identities was a few months ago, but I'd suggest getting the identity of the denominators and then adding till you get the simplified answer.
hope this makes sense
it does
Plz help me the solution is needed
Hints Leading To Solutions To Each Question:
a) How many letters are there? Well, that is the amount of points.
b) What is a ray? Well, it has one starting point and it shoots out and does not end. It is like .---------------->
c) What is a line segment? Well, it starts and end, unlike a line. It is like .-------.
d) There is only one line the question. A line does not end and it goes in opposite directions infinitely. It is like <-------------> So, what are the ways to name a line?
Buddy, it is asked in this server that we provide steps leading to the answer and not the answer (depending on the situation or question).
Ik about this
I came across an interesting problem that i was not able to solve analytically
find the area of the blue circle given that it is tangent to both axes and the graph
convinced 90% are doing a last minute homework assignment
if anynoe is able to solve this analytically please tell me(well up to the point where you need to solve the disgusting system of equations that may arrive, then numerically apprxoiamte it ig)
yeah that variable for the circle really is something. at least x and y are both translated by the same
yep
and in that case, there are numerous of help channels
for immediate help
im not sure i get what you mean
you defined the circle with an equation right?
to find an expression for the point, you can use that dy/dx = dx/dy at the point they intersect
send me the system of equations you got so we're on the same page
you can implicitly differentiate the circle equation (actually only the sqrt(r - x^2) part) and the e^(-x)^2, and then find their intersection in a way, hm? though that's not precalculus, it's just calc
though probably there is a simpler way, just the first idea I've got
a bit late but for 17:
J, K, and L are points on the same segment
point K is between J & L
this means JK and KL are both within the line segment JL
so JL = JK + KL
try putting the equations together
for the first question
you know that angle NEC is 90 degrees as stated in the diagram
so 5x+1+3x+9=90
8x=80
x=10
THANK YOU
can u use the values?
wouldnt that just complicate things?
first just use (a+b)^2 property and then use values
yeah i tried that but couldnt get the right answer
try to convert sin75 into a cosine value then use sum-to-product
y'all are overcomplicating this
what was your answer after using property?
mind helping us 
oh wait now that i think of it, just expand and use pythagorean identity and sin2x identity
answer is 1/2 btw
you mean (a-b)^2?
same formula from different angles, so to speak...
$\cos^2(75\dg) + \sin^2(75\dg) - 2 \sin(75\dg)\cos(75\dg)$
Ann
got it
something might just jump out at you
Ann
hey this is a cool bot
whats the double angle formula?
my god yes this it it
i got -cos^2(75) in the first part
anyways thanks
??
sin2a=2sinacosa
ohk thnx
this bot is cool tho someone has to teach me how to use it 😂
#resources has a cheat sheet
the markup language it uses is called LaTeX, for which you can find tutorials online
#latex-help exists here too
thats a game changer bot right there
sure is
anyways thanks ann, saved me from worrying about this for next couple weeks
now it wont haunt me anymore 
Help please
How do you do this pls help
do you know how to move stuff around on a grid
I do
starting with the point the top right of your figure,
where will it end up after moving 1 unit to the right followed by 6 units down?
- x = 80 y = 70 if the two lines are parallel
- x = 70 y = 110
but my question is do you know the concept of parallel lines tho
i hope that isnt a test
goddamn thats easy tho
This is prob the easiest geometry ever but its kinda hard for meh pls help.
are u in the middle of a test
it was for homework
oh lol
we are gonna have this for the next grade but i think the portion is omitted
not really sure though
3D space angle/rotation . If I have only the first image(no rotation ) i have elevation angle =asin(width/length) and azimuth angle=acos(width/length). Can someone guide me on which angle(s) and how are they influenced by the rotation?
Weekend hw on the day it was due
Is that...
DELTA MATH?!?
I just had to complete this painfully annoying assignment on delta math
Can someone answer this simple question im confused ash
Depending on one's favorite definition of "intersect", one might possibly answer yes, but nobody would ever say "intersect" about two points.
This is the answer I wrote
But the question said nothing about lines.
If you're talking about something intersecting in two points, then that can definitely happen -- for example if the somethings are two circles.
Ur right ima change the answer and thx for the help
But then it's the circles that intersect, not the points.
Technically, you could say yes, as when, for example, 2 lines intersect, they share a point, so if 2 points were in the exact same location, they would share that point, but yeah, you wouldn't say intersect for 2 points.
if I have ||u|| and ||v|| can I do ||u||² = u² ||v||² = v² and then find ||u + v|| in vectors?
what do you mean when you talk about squaring a vector as-is?
if his identities are true, then he is probably talking about inner space product, typically <v, v> = v². other operations don't fit for this channel, so I would assume that
typically I don't think you can get what you want (there is no thing like ||u + v|| = ||u|| + ||v||) and you are recommended to just find the length as usual
you can use the cosine theorem, but I think it's better to just sum up the coordinates and find the length
in 16, x=130 and y = 50
my point is
so I can use u . v = 1/2 (||u + v||² - ||u||² - ||v||²)
yes i believe so
oh, then sure
anybody good at trig?
@icy elbow you should just post your question
What if, that is the question? 🤨
they tried to DM me just now, but i could not DM them back.
Oh
does anyone have all the trignometric formulas and identities
@silent plank could you drop your \trigids thing here?
those were rokabes, they should be pinned here
thanks
Bow do I find the area of a sphere? I wasn't paying attention to that lesson in class lat week
The volume
Thanks
does anyone know how to use the hint for this?
the sides of the triangle are in the ratio 1 : 2 : sqrt(5) by the pythagorean theorem @jagged moon
so this boils down to proving sqrt(5) is irrational
(2) in the first image is cursed. There's an angle labeled z² which makes no sense.
the angle measures are probably all given in degrees and z is supposed to be taken as dimensionless
Yes, that's probably the most likely. I still submit there's no freaking situation where such a relation could possibly arise in a natural way, though.
it's a quadratic equation dressed in a geometric fig leaf
Can someone correct me where I went wrong? I need help please, thank you
This is geometric sequence/series btw
Whoops
ok yeah I figured that too, thanks!
wdym by whether its correct
the question is fine
have you done circle geometry yet?
there's a nice theorem for stuff like this
otherwise use properties of slopes of perpendicular lines to set up an equation
Hey -cosec will be +cosec in the 4th quadrant right ?
The fourth and the third quadrant, yes
you want theta to equal 90, and by the inscribed angle theorem(prop 20 in Book3 of Euclid's Elements), you know that the central angle will be 2 theta = 180, and there's only one way for that to happen, which is if AB is the diameter of the circle. you conclude that P is just a point on a circle of radius AB/2 centered in the midpoint of AB. check here https://en.wikipedia.org/wiki/Inscribed_angle#Theorem
another way to do this is to use analytic geometry and Pythagora's theorem. just compute euclidean distances and write Pythagora's equation AP^2 + PB^2 = AB^2
however, when you expand you'll have to bring the quadric to its canonical form and classify it to determine that it's indeed a circle.
https://en.wikipedia.org/wiki/Conic_section#Discriminant
maybe there's a 3rd approach of using trigonometry, use the parametric equation of a circle but also say that sin/cos are unique
https://www.stumblingrobot.com/2015/10/30/prove-that-sin-and-cos-are-the-unique-functions-satisfying-given-properties/
Let be given functions with derivatives satisfying for all in some interval which contains 0. (Note: and satisfy all of these conditions.) Prove that these functions must satisfy the Pythagorean identity If and are any other pair of functions satisfying all of these conditions prove that What else can …
In geometry, an inscribed angle is the angle formed in the interior of a circle when two chords intersect on the circle. It can also be defined as the angle subtended at a point on the circle by two given points on the circle.
Equivalently, an inscribed angle is defined by two chords of the circle sharing an endpoint.
The inscribed angle theorem...
In mathematics, a conic section (or simply conic, sometimes called a quadratic curve) is a curve obtained as the intersection of the surface of a cone with a plane. The three types of conic section are the hyperbola, the parabola, and the ellipse; the circle is a special case of the ellipse, though historically it was sometimes called a fourth t...
@sturdy trellis Sorry I mean general cartesian form(not canonical). After that, using the fact that discriminant <0 and A=C and B=0 is enough to identify it as a circle.
i still dont know how to do it..
phshs you forget it as soon as you finish it
no a=d and b=c is wrong. that would only happen if PS || RQ (which is not the case).
instead, just use the fact that the sum of interior angles of a triangle always equals 180 and that triangle PTS has an angle with equal measure to an angle in triangle RTQ.
use vertical and adjacent angle pairs https://en.wikipedia.org/wiki/Angle#adjacent
In Euclidean geometry, an angle is the figure formed by two rays, called the sides of the angle, sharing a common endpoint, called the vertex of the angle.
Angles formed by two rays lie in the plane that contains the rays. Angles are also formed by the intersection of two planes. These are called dihedral angles. Two intersecting curves may also...
Let E be a point inside the square of consecutive vertices ABCD that is at a distance of 1 from A, at a distance of 2 from B and at a distance of 3 from C. Calculate the angle AEB.
Any help? No idea how to solve that lol.
I've read a proof of it here https://www.cut-the-knot.org/proofs/swivel.shtml
It requires copying the original figure, rotating it by 90 deg and attaching it to he original figure.
The cool part is this operation will create a new 90 degree angle.
From there Pythagora's theorem and its converse are used to acquire more information and eventually the angle AEB is computed.
thanks
Having a hard time understanding geometry
can anybody help me with this question?
with what how to draw graph?
ok thanks a lot bro i really wanna pass this
wait how are you solving it
its 6
oh god
how did u do that
desmos
??
ohh
can u help me with this?
man its sucking my head
@hybrid lily
got it... its a graphing website
oof we need the whole how u did it thing
can i send u a website with the answer or whati think is the answer
man
how to find y?
@hybrid lily the answers are on ur tips
no i need the equation on how i got the answer
lol im bad at geometry so i just googled it
ur given the equation
lol
x^2-4x+1
yes in the table see it
ohh as you can see im very bad at math i didnt even know this xd
oh lol no prob
i honestly still have no idea what to do
ok u have x= (-1,0,1,2,3,4,5)
the equation is x^2-4x+1
so if u put for example 0 into the equation u get
(0)^2 -4(0) + 1 which = to 1
so the point is (0,1)
then u do that for all the x values to get y
yeah uh thanks for the effort but i don't know how to do any od that i was forced into thi class
yes actually
@hybrid lily hey
hi
wait is this the graph for my thing
ya
so
I'm afraid I might have slipped up and misunderstood some steps to solve this this similar triangle with missing side problem
based on the formulas I know
I couldn't get the UT side length
since there isn't any KM side length either
am I supposed to solve for the KM side length first?
was there additional stuff indicating which sides/angles were corresponding
$\triangle ??? \sim \triangle ???$
ℝamonov
Why use synthetic methods when you can also solve the problem?
Broadcasted at https://www.twitch.tv/vEnhance (runs Fridays 8pm EST, schedule at https://web.evanchen.cc/videos.html).
Come join my students in watching me be dumb on camera, whether it's missing MathCounts questions, misreading shortlist geometry problems, forgetting a Spawning Poo...
What's that set up for geogebra? I don't have an input command line below like he does
wait got it
it was the classic version
The classic version is so much cooler
I'm gonna try hard at geometry, maybe I'll be around here often 🙂
nope, that's all they gave me
can you triple check.
90% of the time I ask this, some new piece of info pops up upon asking the third time
that's all I got
i suppose you assume that the diagrams are reasonable scaled
i can't tell if lm coincides with tu or uv lol
UV looks a bit longer than TU
ah true
I see
alright I'll try doing that
I'll ask my teacher for clarification as well
thanks for your help
In geogebra, how can I hide the angle measurment of an angle
Right click on it and then settings and then find a checkbox called “show object”.
Also when you right click theres a menu and you can disable there
I can check "show label". But I want that option disabled all the time by default, so I don't have to do it every time I draw an angle
Geogebra can probably do that(it has a lot of features and docs and a forum) but I may lack this knowledge.
Sometimes I want to do custom or complicated things with it but I realize the time spent would lead to a marginal improvement so I try to focus instead and make compromises.
But if I find a way to do it, I’ll share it.
In advanced settings, you can modify some aspects of angles (like change degrees to radians, etc). The option should be there I suppose, but didn't see it. I also tried googling, but couldn't find anything
I'd assume they're right triangles, so, you'll find the value of side KM using the Pythagorean theorem, then, use the solution of a right triangle to find the angles. I've not really encountered such a problem before, but it's intriguing. Again, I'd assume after getting all the angles in Triangle KML, the values of the angles in Triangle VTU will be the same as in Triangle KML. Therefore, you'll have the appropriate values you'd require to find the other missing values of Triangle VTU (particularly the 2 sides)
take this with a grain of salt, as I relied on the word "similar triangles." Such a shame that I've not known the term when I self studied plane trigo, lmao
Thank you very much
it's starting to click
like wow! I didn't know there was such a big gap between linear systems and trigo
maybe I just find trigo harder
you shoulnd't be assuming right angles
you are not being asked for VT or KM
only TU
yes
if thats the case, i honestly have no clue how to solve the upper triangle with only one given value, even if it's a right triangle
the triangles were given to be similar
the issue was identifying which sides/angles were supposed to be corresponding
but if they're right triangles and their angle values are similar, i think you'd need angles to find the value of side TU

