#geometry-and-trigonometry
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correct
this serves dead haha
Hint: take the coordinates of each vertex of the triangle and multiply it by the scale factor.
when multiplying 2 to the coords
I did
lol
and then after that
I added (2,2) to all three of the scale factored coordinates
that didn't work cause I got 14 as the y for the second coordinate
so I decided to subtract each of those three coordinates by (2,2)
and got this graphed
@hard gale
i guess you just screwed a calc somewhere, the two other points are fine
this one is odd tbh
yeah
FACK
yeha idk what I did wrong
2(0,6) = (0,12)
then
(0,12) - (2,2) = (-2,10)
oops wrong one
ah i see
i just haven't done this shit for long times lel
looks bettre
ik but is the math correct and all cuz with dilations it can look alike and whatever but the calculations matter
the math is ok
however just think to compute the coordinates with the new origin first
for some transformations it matters (like rotations)
This one idk
I keep getting decimals for my x
What should I do here
last question
you should substract the coordinates of the origin first tbh
it's like with functions, as in usually f(g(x)) =/= g(f(x))
Okay so what I got for the scale factored coordinates are, (-2.5,2) (1.5, 4) and (2.5, 2)
so just subtract these three by (-3,0)?
what i mean is substract -3,0 from the coords of all the points then perform the dilation on those new coords
k
I got this
(-5,4) - (-3,0) = (-2,4)
(3,8) - (-3,0) = (6, 8)
(5,4) - (-3,0) = (8,4)
^ calculations
REEEEEEE is it right?
cause for the second part with the x I did, 3 - (-3)
@hard gale cmonnnn
almost done haha
yea so now do the scaling
(a huge pack of flour fell in the kitchen and it was everywhere lel)
and now retranslate back
what
did that already
you still have to get the coordinates with the original (0,0) origin (since (-3,0) became our new (0,0) in 1st step basically)
I'm confused
(-1,2) (3,4) and (4,2)
what do I do with these coords
since they have already been factored
jesus
Can someone help
I've been on this 5 question quiz for an hour and a half
lol

If youre out of coleslaw, use sine law
hi guys im super dumb
it doesn't describe where to rotate the shape
i mean it does tell us to rotate the shape 180* clockwise but... at which point do we rotate it from? it never said the origin
i assume you would rotate the shape around either the non coloured point or around the origin but I don't necessarily know how to do it!
translations and reflections are easy but not rotations for me...
@teal mortar I would say assume the origin unless the question specifies a location
how do u rotate around the origin im having a hard time trying to plot the points
do you need assistance in understanding rotations easier
yes please
ok
someone said you rotate around the non coloured dot but i said that doesn't make sense because the shape might go outside of the actual cartesian plane/graph thing
give me a second please
okay np
Lets assume we are rotating around 0,0 the origin
yes
one second, I will get a visual
ok
the radius to point A
no need, there is a faster way once you see the trick
do you know what color is the 180 rotation?
green
ok good
what are the coordinates of the green dot?
(3, -3)
how does it relate to the original location of A?
coordinates
what do you notice
check it out and see
๐ฎ
i see it !
okay
would the story be different if it was rotating counter clockwise?
yes and no
VERY NICE
okay hold on.
so for A if u rotated it 90 degrees clockwise it'd be (3,3)
oh!
all the numbers are positive?
so they're all in quadrant 1
i do suggest you look at the coordinates for 90 degrees clockwise counter clockwise as well
so B would be (7, 5)
focus with point B
b is currently at (-7,5)
nope
..
different trick for 90 degree rotations
ok, let me know if you want a hint
yep
yes
rotate the paper you have 90 degrees either way it doesnt matter, and travel the same up 5 and over 7
starting from 0,0
keep rotating the paper 90 degrees
ok ok
to get to be we go up 5 and over 7 to the left
i go 7 right 5 down
then after do i go 5 down and 7 left?
ignore B for now after you rotate the paper
ok lets try a different simpler approach
okie :3
so the trick to 90 degree clockwise rotations..
would A be 0, -5?
nevermind
it would be 5, 0
yessir
nevermind !
i just saw something
XD
since i found out A
A'*
i can plot out the rest of the points lemme send a pic when i did it
like this ?
@teal mortar
that looks pretty good to me, do you see any patterns in the coordinates and how they change from A to A', B to B' ect?
alright so
what i notice is
A: (0,5) B: (6,3) C: (9,8), D (1,10)
^ for original pic
shape* but the coordinates for A' B' C' and D' are: A' (5, 0) B' (3, -6) C' (8, -9) D' (10, -1)
so like the numbers are opposite and the y number becomes a negative.
i also notice that rotating a shape 180* counter clockwise is the same as rotating it 180* clockwise i think
keep going
nice
is 270 ccw similar to a different rotation you have already done
uhh, one quadrant is 90degrees so u can keep that in mind but u should know lo
yea
๐ค yesssssss?
yesu? :V
checking a something
sorry my english atm is really bad cuz im tired but i wanna do this because i think im starting to understand it now
you got dis
yes its good
the drawing in quadrant 2 (top left) is my 180 turn
it said counter clockwise
tho
but i just rotated it clockwise instead
would it make a difference or no?
wonderful, if you want a challenge, try doing the rotations without a picture at all, only use coordinates and the patters you see
o boi i dont know if im ready for that XD
so it doesnt make a difference if i rotated 180* ccw or 180* cw?
ah but you are, you are already seeing patterns in the coordinates,
yea
well to be quite frank
i just find A'
the coordinate ^
then i figure out the rest of the points by just like plotting them according to the points i see that are already listed for the original points
this is good -> ๐ป Chr๐ พma ๐ป: so like the numbers are opposite and the y number becomes a negative.
yeah, just finding one point is enough to fill out the rest
Original shape: A. (0, -1) B. (8,-4) C. (6,-9)
and so as soon as i found A'
(0, 1)
i was able to find out the rest of the numbers
lo i dont care too much about the patterns, i just visualize it... which is my preference
1000 iq
so what do you say the pattern is for the coordinates in that one?
A' : 0, 1
B' : -8, 4
C' : -6, 9
all the numbers on the left are negative
all the numbers on the right are positive ๐
but you have a 0
๐ค
neither
0 is just 0 loo
can I suggest slightly different wording?
I would say the sign of the x coordinate is opposite
then there's me who doesnt git 10 trig problems
I would strongly suggest you keep looking at how the coordinates change and keep getting a better understanding of it
come up with your own "rule" to follow that always works
lo perfect description
i just gotta find that correlation
1
bottom left pic is the 2nd shape after rotating it 90* ccw
close...
whats up
thats a reflection
oof
over the x axis
oH
i looked at it and i said
wow that looks like uh
a mirrored photo
lemme refix.
just wondering
if the original A is ( -2, 4)
does that mean A' would be (-4, -2) or (-4, 2)
nevermind
plot both, one looks right one does not
how would you describe the change and repeat it for the others numerically, without the graph
hmm
how would i
im thโญnking
well some numbers like the x switches with the y
YESSSSSSSSSSS
some of them go from negative to positive and switch and stuff
AND!
um
MORE!
bring it all together
yes good
I am a licensed math teacher
and chroma should prepare for questions where you do not get a graph
no wonder u were so enthusiastic
the numbers switch from x to y and vice versa, the numbers also go from negative to positive and vice versa
this sounds better and better
i.e. moving a shape 180* cw
original points: A. (-3,3)
B: (-7, 5)
C: (-10,10)
now if you were to rotate that 180* cw or ccw you'd get
(-3, -3)
(-7, -5)
(-10,-10) so basically rotating it 180* cw or ccw makes the numbers all negative?
hold up
hmmm
one sec
the previous problem said 90 degrees
dont worry, i feel retarded at times too
ahh you see
...?
this one is now saying 180
1st question I showed you showed rotate it 180*
2nd question I showed was rotate 90* clock wise
3rd question I showed was rotate 180* ccw
4th question I showed was rotate 90* cw
i mean ccw for 4th question ^^
but i dont think my hypothesis for rotating it 180* makes all the numbers negative or something
will the ptterns be the same for them all, or will they have different patterns?
damnit its hard!!! i just see patterns
they have different patterns
according to where they are?
good good
yep
oh yes
no
try a point
oh wait
3,-4
i read that wrong
ya
the plots are diagonal from each other XD
if i started with -3, 3 then 180* would be -3, -3?
cuz thats what i just got
(3,-3)
its good
yeah, points are basically diagonal to each other
and earlier we said +,- goes to -,+
i assume it'd be vice versa if it was (+,-) then it'd be (-,+)
mhm.
there's so much to remember for like making up my own rules!
so how can we describe this generally for all 180 degree rotations
opposete, say more
so if the points were in quadrant 1 and were rotated 180; the rotated points with be in quadrant 3
depending on which one is negative and positive
what does opposite mean
i.e if the number is (-4,5) and you rotate it 180* then the opposite would be (4,-5)
ah, opposite sign for x and for y
that is 100% always correct
uh
(-4,-5) = (4,5)
idk XD
im just making everything opposite signs
is my hypothesis correct
but only for 180
use your abilities and graphs to plot known points and look at the coordinates
but screw sleep
XD
jkjk
i really value it but i also dont
ill start to value it more as i grow older.
seem right?
lmao i sleep an average of 6 hours
i sleep about 7
cries
and i need about 8
ok, now for 270 degrees xd
very well formatted
kinda yes
270* ccw is 90* cw
better thankls
which is also 0
smh i was just testing
mhm.
hell yeah
seems good
i dont know what happens if the numbers are (-,+) and if the numbers are (+,-)
REEEE
oh lawd have mercy
(-,+) ---> (+,+)
wait..
i think..
yeah
and so (-,+) ------> (+,+)
wait
or am i just wrong
or its just the opposite
90* is much more complicated than 180*
(+,-) -> (-,-)
xdd
let me give you a few 90 degree cw examples
4,5 -> 5,-4
-1,3 -> 3,1
-2,-5 -> -5,2
4,-3 -> -3,-4
what do you notice
the pattern is more than just signs
both positive ones: (+, -)
negative x and positive y: (+,+)
both negative ones: (+,+)
x positive and negative y: (-,-)
so
hmm
negative x and positive y is = to both negative?
x positive and y negative is = to both negative
both positive = x positive y negative
focus on just the numbers not the signs for a moment
its hard
what happens
the signs kinda make sense
- 4,5 -> 5,-4
- -1,3 -> 3,1
- -2,-5 -> -5,2
- 4,-3 -> -3,-4
- the x and y switch spots and y becomes negative
- both numbers become positive
- both numbers become positive
idk if my method helps but here :V
try to avoide breaking it up into different examples
look at all 4 examples and make one rule that works on them all
now what's different about cw
erm
im not good at doing stuff like that sorry
i do notice one thing in common.
what
so 4,5 -----> 5,4
i only understand the x and y numbers switch spots
4,5 -> 5,-4
yea
4 swaps and becomes negative
the x becomes the y in the 90* one?
it changes signs
so opposite positions and opposite signs
-1,3 -> 3,1
y swaps but...
y switches positions but stays the same
bingo
does that apply to all of them
(-,-) (-,+)
(+,+) (+,-)
they swap
does that idea of x opposite side and x opposite sign and y opposite side but same sign work for all
or no.
check it
- 4,5 -> 5,-4
- -1,3 -> 3,1
- -2,-5 -> -5,2
- 4,-3 -> -3,-4
tbh i cant really check its 11:30pm and i should be in bed ill only have 7h of sleep
ok ok
it works.
then before you leave
now thats math right there
XD
๐
one sentence for all 90 degree cw rotations
but what about 90* ccw and 270* cw and 270* ccw
could one of you guys dm me about it because i gotta sleep soon
like very soon
ok
so i just say
270 ccw: 90* cw
how do i do 90* ccw
so basically all i need is 180*, 90* ccw, 90* cw?
the wording you just used for 90 cw is almost the exact same for 90ccw
haha
im tryna figure out
my brain is just dying at this point but im starting to get a grasp
you will be the best learner if you do this one on your own
take a break after writing down the 90cw one
instead of finishing my homework im doing this math concept stuff and its rlly cool and ill share with my class
come back another time
wait
sleep is no1 priority
can you give me some numbers so i can test my hypothesis
its good to take breaks when you are actually learning hypothesis and stuff
will dm you
im so excited to share this with class
ok thx
I'm so excited to share this with my class.
happy to hear
thanks to u guys u helped me a lot
...but i probably didnt help
now i can complete the rest of my hmwk at school before math and ill understand everything
u did help! u helped confirm my theories and stuff
thx โค
what is another way to write csc(x)
1/sin i believe
yeah
so what is csc(x)sin(x)
1
yes
yes
yes intensifies
what's another way to write 1
imma fail high school math then
unsuuree
n
gn
yeah kk
@me if you need

theta
yeah
cos^2(x)/sin^2(x)+1
then u get cos^2(x)+sin^2(x)/sin^2(x)
end result is csc^2(x)
that's right
wait they put the answer as sec^2 on the sheet
or is that something else
oh
is it multiple choice
nice
i learned more from u than my math teacher lo
probably cuz im slacking off 90% of the time
prob
yeah...
waat
Hi. I'm new to math.
I had a question.
How come the digits of the constant pi can be 0s?
if it is a 0, how come it doesn't end there and then more digits follow? and there are lots of 0s.
the same way the number 101 has a 0 but doesn't end there
hmm
but why can the digits of the pi have a 0, does that not kill its accuracy?
I was thinking it may be picking the number between 1 and 9 based on how accurate it is.
(and yeah, I don't understand any math, but interested in learning )
0 in this case has a value of its own
who they speaking to lol
idk
Cotx(secx - cosx) = sinx ๐ค
?
How can i find the trigonometric values of cos(150ยฐ);sin(150ยฐ)?
Know your unit circle.
Find the slopes of the two opposite sides of a parallelogram and show they are identical?
@upper karma how when I donโt have the coordinates
Well, aren't you going to create a coordinate system for the parallelogram?
Oh, sorry, I keep jumping channels, sorry about delay. OK, can you draw a parallelogram on a Cartesian grid?
yes
OK, do it and then check the slopes of the two parallel lines
Wait wait @serene field how did you get that?
By definition of parallelogram, opposite sides must be parallel
I just chose equations that gave whole number coordinates.
So I just gotta draw that and show the slopes for it to be proven right?
I don't know much about coordinate geometry, but going off the name, you may want to instead use the coordinates of the vertices.
Prove that the slopes between adjacent vertices are equal
Pretty much, yeah.
Ok thanks for your help!
No problem, feel free to ask more questions as you come across them. ๐
You know how we used the slopes of the parallelogram to prove the earlier thing?
Yea
Pretty much the same thing here.
Rather than slope, you're just looking for congruency
Distance formula will do
You can just draw an isosceles trapezoid on a coordinate plane with vertices on whole numbers
What points should I choose though?
Whatever points you like. Drawing something sideways might make computation slightly harder though.
Having your base on the x-axis might make computation easier.
Looks like that will work, though.
I graphed this one for one of my earlier problems
Iโm just gonna finnessed it so I donโt gotta do slope again lol
Since you're looking for congruency, distance is probably the way to go.
Thanks
@serene field when I show my work I gotta find the distance for DB and AC right ?
Or do AD or BC work?
@dawn stone
yes mate?
Can you help me with #7?
umm
you could take different points that satisfy the equation, and then plot a graph connecting those points?
Uh wdym
like take y=0, then find out the value of x that satisfy the equation
then take y=something else, find the value of x again
similarly, find multiple points in this manner and then join them on the graph
4
So itโs a V?
so your first two points are (4,0) and (0,0)
Basically only need 2 points to graph it
then you try finding points with different values of y, and finally connect them
You need more than 2 points to graph anything
always
Since this has double absolute values, you may want to check both the positive and negative side.
yup, you got 2 points for y=0, then next try y=1, y=2, y=-1, y=-2 and once you feel you have enough points graph it
|x-2|+4=5
My intuition is saying this is a square/rectangle shaped graph.
Yep ^
you pinged me, but I don't see your question
I already explained these in the other chan to you the other day right? Where are you stuck at?
Can you check the ones without theorems next to them since Iโm supposed to have one next to everyone ? Also check if the ones I did are right @dawn stone
did you just copy the answers to them I gave you earlier? Cuz you don't even have an X in your figure in question 4 yet you've used it in solution
that's bad mate, you won't learn anything that way
I just imagined it
Iโm gonna redo it on paper later
Just making last minute revisions
@dawn stone
mhmm, the solutions are fine though alarmingly identical to mine. Anyway looks good, proceed
@serene field the unit is 1
did you solve i and ii already @forest hazel ?
do you know the power of the point theorem?
how did you solve it?
Uh formula sheet and some manipulation
But when it comes to tan 8x
Idk how the heck to convert it
yeah prolly formulas for sin(2x) and cos(2x) right?
Yea
you could try to rewrite tan8x to sin(8x)/cos(8x) ?
I did formula for tan (2x)
see if that helps?
And dk how to proceed
I did
I kinda uh got stuck
Because there's the 4 there
That idk how to get rid of
How do I convert it because there's the stupid 4 there that I cant exactly use
I need to get it down to at least 2x
then repeat
cos(4x) you know already
sin(4x)=2sin(2x)cos(2x)
I just realised you can't really determine tan(8x)
you can get |tan(8x)| but not tan(8x)
@restive wren do you still want help with that?
Yes
can you repost?
so have you heard of the power of a point theorem
also known as intersecting chords theorem
for what?
I am in high school ,so no
The question I posted jn
$|sin(4x)|=\sqrt{1-\cos^2(4x)}=\sqrt{1-\frac{1}{4}}=\frac{\sqrt3}{2}$
Gonzo17:
$|\sin(8x)|=2|sin(4x)|cos(4x)=\frac{\sqrt3}{2}$
Gonzo17:
I think you can see where this is going
yea, cause we can only get |tan(8x)| this way
ok @restive wren sry for that break
im trying to make some formula that output the width (widest point) of a regular polygon with the same area as a square with x width.
Is this even posible, not that good at math myself?
-inputing 3 and 100 would be 133,333...
-inputing 4 and 100 would be 100
-somehow inputing infinity and 100 would be 112.83...
@steady hull why not just evaluate for the values?
Kermie is op he got it already
i don't understand why he couldn't just evaluate the equation?
Probably cause itโs not very elegant to evaluate the values using a calculator and show that they sum to 0
Holy shit my grammar
Sum to product I think
luka:
how do I prove that this works for any real number x?
<@&286206848099549185> any ideas?
cos(x) = cosยฒ(x/2) - sinยฒ(x/2) = cosยฒ(x/2) - (1 - cosยฒ(x/2)) = 2cosยฒ(x/2) - 1
luka:
$$cos(x) = cosยฒ(x/2) - sinยฒ(x/2) = cosยฒ - (1 - cosยฒ(x)) = 2cosยฒ(x) - 1$$
$$2cos^2 x - 1$$
luka:
wait
that's not x/2?
wait I'm tired and thinking (or trying to)
luka:
how do I know that?
ok
cos(x) = cosยฒ(x/2) - sinยฒ(x/2) = cosยฒ(x/2) - (1 - cosยฒ(x/2)) = 2cosยฒ(x/2) - 1
yw
are my points right?
Heres my calculation
(5 + x2)/2, (-6, y2)/2
I solve for x2
8 = 5 + x2/2
16 = 5 + x2
11 = x2
Then
Solve for y2
5 = (-6, y2)/2
10 = (-6, y2)
16 = y2
<@&286206848099549185>
U can check urself
Whatโs the midpoint of 11,16 and 5,-6
@sick veldt
Anyway yes it is right
The way u calculate midpoints is by summing the x, then divide by 2
And doing the same for the y
Sure
Thanks
So
Just find the mid-point
then fine the midpoint of the same found midpoint with point A
find the midpoint between point A and the mid-point basically right?
how do I get $$cos(pi/8)$$
knowing that pi/8 = 1/2 * pi/4
I have to prove that it's equal to $$\frac{\sqrt{2+\sqrt{2}}}{2}$$
<@&286206848099549185> any ideas?
there are half angle formulas
*I need to use the duplication formula
luka:
so set $x=\frac{\pi}{8}$ just for easier notation
Gonzo17:
ok
you know cos(2x) already
luka:
and on the other hand it's $\cos(\frac{\pi}{4})=\frac{\sqrt2}{2}$
Gonzo17:
what?
luka:
Compile Error! Click the
reaction for details. (You may edit your message)
$$\frac{\frac{\sqrt{2}{2}+1}{2} = cos^{2}(\frac{\pi}{8})$$
any ideas how I correct this?
$\frac{\frac{\sqrt{2}}{2}+1}{2} = cos^{2}(\frac{\pi}{8})$
Gonzo17:
was just missing 1 brace
luka:
Compile Error! Click the
reaction for details. (You may edit your message)
$\sqrt{\frac{\frac{\sqrt{2}}{2}+1}{2}} = cos(\frac{\pi}{8})$
Gonzo17:
on the left side of the equation
yep
but what I'm supposed to get is $$\frac{\sqrt{2+\sqrt{2}}}{2}$$
luka:
rip
yeah they're equal
how?
$\sqrt{\frac{\frac{\sqrt{2}}{2}+1}}{\sqrt{2}} = cos(\frac{\pi}{8})$
lol
sqrt for numerator and denominator
$\sqrt{\frac{\frac{\sqrt{2}}{2}+1}{2}} = \frac{1}{2}\sqrt{4\Big(\frac{\frac{\sqrt{2}}{2}+1}{2})}=\frac{\sqrt{2+\sqrt{2}}}{2}$
lol
Gonzo17:
hmm is there an easier way to convert it?
I mean, this is pretty much simplyfying
you wanna get the denominators out of square roots
I can understand $\sqrt{\frac{a}{b}} = \frac{\sqrt{a}}{\sqrt{b}}$
can you explain with that method?
luka:
$\sqrt{\frac{\frac{\sqrt{2}}{2}+1}{2}} = \sqrt{\frac{\sqrt{2}+2}{4}}=\frac{\sqrt{2+\sqrt{2}}}{\sqrt 4}=\frac{\sqrt{2+\sqrt{2}}}{2}$
Gonzo17:


