#geometry-and-trigonometry
1 messages · Page 191 of 1
If you have to ask here to verify the answer, you don't understand it @upper karma so stop
Ask only if you get the wrong answer and don't understand why
you should verify it yourself and make sure it's right on your own
not guess then ask here if it's right
im only 12
im trying to learn geometry
none of this is for my benefit
if it's not for your benefit then don't learn it lmao
it is for my benefit
i just don't gain anything but knowledge
Is this proof correct?
you just said it wasn't
you highly underestimate the value of knowledge lmao
…..?
good luck being a redneck who don't know whether the earth is flat or nah
wow..
he's being rude to me because im asking help
you didn't ask for help lmfao
you just asked someone to verify your blind guess
it wasn't a blind guess
then answer me, why would that answer not be right?
ive been stuck on the same problem for 35 minutes
because their not congruent
but that makes no sense because length wise, they look like they are
whats not congruent
that's what i meant
parallel lines that is
idk dude haha
I just need to know if my answers are correct
next time
Explain what you did like I did
after sending a question
<@&286206848099549185>
help pls
I need help with this
15 min already
Number one might be a rectangle
and the last box might be SAS
Yeah that’s not the definition of a parallelogram
Parallelograms don’t have right angles
right
And for the last one?
it would be HL
cause it does have a rectangle
with right angles
Yeah that’s HL I think
HL is just specialized SAS anyway
Where the angle is right
Looks fine to me
I don’t rly remember all of the terms from geometry but
Well BC and DE being parallel would make ABC and ADE similar
How would you contradict that
Looks like the second option
Yeah
!help
Perhaps you should use a fraction
Do it sir
thanks
@sick veldt still need help?
No I answered that already
This one I'm working
on
I haven't graphed it yet
but heres what I have written down so far
Well idk about that graph thing so 🤷
But I can tell you about the perpendicular line
The point at (4, 3) should be at (4, 4), since we’re doubling the distance from (-2, -2) to (1, 1)
guys, if i want to find the x intercepts of 2sinx + 1 = 0, the first one is -1/2 and second is 7pi/6. but how is the second one found?
Yue:
The sine inverse function yields the quadrant 1 or quadrant 4 solution.
In order to find the other solution, we take a look at the unit circle.
=pup derivative sin^2(x)-2cos^2(x)
proof by wa
It's got a nice expression surprisingly
🤕 my chain rule hurts......
My calc 2 professor made this one of our standard derivatives actually
so you can write $\sin^2$ as $sq\circ\sin$, with $sq : x \mapsto x^2 \$ therefore $\left(sq \circ\sin\right)^{'} = \sin^{'} * (sq^{'} \circ \sin)$, ie $$ \boxed{\left(\sin^2\right)' = 2\sin\cos}$$
almost the same thing for cos^2
wat
The fuck did you do lol
fack tex
emeric75:
is this an identity?
so concise lel

So if the slope of a line is the tangent does that mean the hyptonese of a triangle is equal to the tangent?
Because tan = a^2+b^2= c^2 or sin/cos =tan
The slope of a line is it’s gradient
Is it’s rate of change
I’m not sure exactly what you mean by the slope of a line is the tangent
If you put it into context
Suppose I have a car which drives at 3m/s east and 4m/s north
Then the car is driving 5m/s at an angle of x = tan^-1(4/3)
But yeah could you elaborate more on your question?
@queen socket
Like in a unit circle your hypo is equal to one and your x = cos and y = sin and using the trig identity x2 +y2 =1^2
So your hypo is also the length of the radius of the unit circle
For me I would say you are overthinking it a bit, the tangent to something is the straight line or plane which touches a curved line or surface at one and only one point
To call the hypotenuse of a triangle the ‘tangent’ is a bit strange to me
Oh okay
But I would also ask someone else because I could be completely off
sorry I couldn’t give you the answer you may have been looking for
I just looked it up, it says the following in calculus, the slope of a function at a given point is the slope of the tangent line. However, not every line with the same slope is tangent.
No I know what a tangent is with calculus
I meant I could be off about the trig stuff
Is the tangent the hypotenuse, maybe 🤷 I’ve never heard of it personally
Thats all good, have you been unbanned from piano yet
Lol nope
Unlucky
derivative of 2/(x^2+2x) is wrong
why?
try using the full quotient rule instead of the chain rule
d/dx (u/v) = (u'v-v'u)/v^2
idk how to use the LaTeX bots so can't write it out clearer 😄
do u know the quotient rule? or have u used it before?
I got -4x-4 / (x^2+2x)^2
Fixed
but that what I sent
oh yea
well derivative calculators are giving me the answer in a different form
they factorise the denominator into x^2 (x+2)^2
i dont understand
sorry u were correct all along haha
my english is very bad
i think
hmm i can't think why it is marked wrong#
try just expanding the denominator into the form x^2*(x+2)^2, even though it should be equivalent the computer may only recognise it in a particular form depending on how the question is coded
i worked for my uni's maths department writing online quiz questions... sometimes it can be difficult to code such things to recognise all inputs
=pup derive \frac{1}{x+2} + \frac{2}{x^{2}+2x} - \frac{1}{x} + 3
=pup derivative \frac{1}{x+2} + \frac{2}{x^{2}+2x} - \frac{1}{x} + 3
?!

well i didn't anticipate that
if its a half decent program it should recognise that it simplifies to zero on its own
=pup derive \frac{1}{x+2}
=pup derive \frac{2}{x^{2}+2x}
ye he got that
Try writing the minus out of the fraction
So instead of -1/2
It’s -(1/2)
I know it’s the same but computer tests are retarded
they are... very xD
Hello
no
need help here. i did a method but i think i messed up somewhere
is there a formula for sinθcosθ again?
ok thanks
im rechecking my work then ill ask for help again
ahh ok i found my mistake
thanks for the assistance btw
Does anyone know how I can find the legnth of x
Make a triangle with x as the hypotenuse
Relate the side lengths of the outer and inner triangles
Pythagorean Theorem to solve for x
Thanks
Not sure where this goes but what is this problem called?
Given a polygon P with holes (obstacles inside P) and a point q, find q' that is furthest away from q (Euclidian distance) and not on a boundary of P
what are the conditios for 2 segments to intersect?
defined each segment with 2 points
The slopes have to be different
something else?
Stuck on #9 pls help
Ive got the solutions pi/6 and pi/3 but not the other two
There are 2 solutions in (0, 2pi]
Look on the unit circle to see where sine is positive and has the same reference angle

Lead has a density of 11.35g/cm"3. Calculate the maximum number of lead spheres of radius 1.5mm that can be made from 1kg of gold
@chrome fiber if you can help be that would be awesome!
😦
guys help

we have three points: A(-1,3), B(1,4), C(3,y)
they are collinear
we wanna find y
how can i do that ?

the line connecting those points would have the same slope
or u could connect those points and say that the area = 0
and then solve for y
let me try that first one then i'll come back with the results
ok solved thanks
y = 5
hi can i also post a question here? or does it have to be in the questions channel
it's about analytical geometry
you can post it here
thank you 😃
Q: if the line segment connecting (x, 3) and (5, y) is bisected by the point (7, -5) , find the value of x and y
i tried to come up with equations however still haven't found the answer
bisected, ie the point in the middle of the line segment is (7, -5)? (my geo vocab in english is pretty bad)
bisected means it divides the line in two specifically at the middle
oh wait hahaha
i think i get it now lol
i was thinking point 7,-5 is not the one in the middle
oof
👌
Lead has a density of 11.35g/cm"3. Calculate the maximum number of lead spheres of radius 1.5mm that can be made from 1kg of gold
pls help meh
"Calculate the maximum number of lead spheres of radius 1.5mm that can be made from 1kg of gold" dafuq?
Density*volume=mass
Convert the g/cm”3 to kg/m”3
And find the volume of each lead sphere(4/3 * pi*r^3)
Multiply both to get mass of one lead sphere
Then equate the masses to find the no. Of spheres required
sure, ask your question
so this question says “(3,-7) and 3x-4y=12 write an equation for a line perpendicular”
i literally know nothing of what i’m doing
What is the slope of a line that is perpendicular to another?
More specifically, what slope will be perpendicular to the given linear equation?
the relation is given by (slope1)*(slope2) = -1
lets say the slope of a line is 5, then the slope of a line perp to it is -1/5
Lead has a density of 11.35g/cm"3. Calculate the maximum number of lead spheres of radius 1.5mm that can be made from 1kg of gold
plz help
bk thx but i dont think that worked
sorry i never responded back, but i understand my question now so thanks
I need help with factoring
@trail helm go ahead
Hellp
I need help
So I have 10th grade math right now and I need some help about similar triangles.
Like SOH CAH TOA
IM in 8th grade geometrey rn and my teacher is useless
maybe I can help you
I need help with factoring
10x^2 + 27x + 5
so basically u need to transform that on a factored from
gimme a minute
imma solve it for you
do you know the criss cross method?
do that to find the factored form of that equation
imma show the procedures to you aight
2x^2 + 27x + x
the exponent will be gone
Yue:
We can then factor by grouping.
that procedure is way too confusing
@frozen saffron Thank you
That makes sense now

I got (5x+1)(2x+5)
I think thats right, right?
I mean you need to have the same result like in the middle
if you cross multiply
So can someone help me about my similar triangles thing?
I need a help about SOH CAH TOA
Does anyone know how to find the missing angle
,rotate 90
Draw out your diagram
Looks right.
im a grade 10 but ill try to help
add up the angles on the left 37 and 58
or whatever they were
then use tan(angle on left)=x/9.8
tan because the angle in question is adj and u are trying to find the opp so tan uses that
to solve just do tan of the angle then multiply by 9.8(cross multiply)
^^^^
not sure if correct but pretty sure
yeah its fine
It only implies the angle of elevation from the anchor point to the top of the tower is 58 degrees from the base, not 58 degrees on top of the 37 degree angle
If it were 58 degrees on the 37, that would be > 90 and there would be an obtuse angle.
owo, so its not a right triangle 🤔
oh ur right
We have a triangle with two known angles and one side. We can easily find the third angle by the sum of angles of a triangle. Law of sines should quickly find the solution.
lol rip sry
damn big f
This question threw me off too. 🤔
Don't really need the 37 degree thing, as far as I can see it.
Anyways, can i get some help on this?
Maria needs to load cars onto a transport
truck. She is planning to drive up a ramp, onto the truck bed. The truck bed is 1.5 m high, and the maximum angle of the slope of the ramp is 35 degrees .
How long should the ramp be? Round your
answer to one decimal place.
Draw your diagram
so basically sin(35)=1.5/x.... hopefully lo im not a math person
You know you have a right triangle and can find all angles via sum of angles. Law of sines looks like it'd work here as well.
same
Then work with SOHCAHTOA
Have you created your diagram?
i ahve but cant send a pic
but angle on left is 35
and height (or opp to angle) is 1.5
m
You have multiple ways to go about this, but your goal is basically to find the length of the ramp.
Tbh, based on the question, I'm not sure whether they want the second leg or the hypotenuse. 
the hypo
thats what i thought
but i did both
and did not get either of them to what the ans was
Well then, look at your trigonometric ratios.
Only sine and cosine have hypotenuse, so those will get us to the hypotenuse.
owo
With respect to the 35 degree angle, for example, we would need to use sine.
As we don't have the length of the adjacent.
With respect to the 55 degree angle, cosine would be needed, as we don't have the length of the opposite to that angle.
Either way, you can solve for hypotenuse.
okay thanks for that. I will try it out
is this question possible without a graphic calculator? i seriously have nowhere to start with solving this
@summer barn what formulas do you have that relate cosine and sine?
cos^2x+sin^2x=1
Peggy’s Cove Lighthouse in Nova Scotia is possibly the most photographed lighthouse in the world. The observation deck is about 20 m above sea level. From the observation deck, the angle of depression to a boat is 6°. How far from the boat is the lighthouse, to the nearest metre?
^^^^^^^^^^^
can i get some help w/ that please
did you try a picture?
They cram so much useless shit into those questions
left*
okay which side is the side youre trying tosolve for
opposite to the angle right?
Hypotenuse
pretty sure they mean the bottom side
that is the distance from the lighthouse to the boat
k so if i were to find the bottom side,
i would do tan 6=x/20
but that leaves me with 2.1
which is not the answer
and i fi were to solve for hypotenuse,
i would do cos 6 = 20/x
ohh i think i got it
my problem was with doing the tan not rounding
but thanks for your help!
np
I actually need a bit more help lol
If you were in a hot air balloon at a vertical height of 500 m above the ground, at what angle of depression would you look at a point on the ground 800 m horizontally on the ground from directly under the balloon?
you need to use an inverse trig function on your calculator
otherwise it's solved the same as the last problem
try drawing the picture first
is it arctan (800/500)?
seems right
Boi
@upper karma ?
one does not simply move on from trigonometry
I mean, I haven't done trig stuff since calc 3-ish 
@burnt relic find CB using pythag
ive done that
find the scale factor
^
I would find angle BAC and use tangent, but that works too 👀
^
tru
@serene field yeah thats prolly better lol
CB = 2, 2.5/2 = 1.25, 1.25 * 3 - 3 = 2.5
wait
hmm looks right
mine
Idk what you're doing
lol same
<BAC: cos(t) = 3/sqrt(13)
Once you find t:
tan(t) = 2.5/x
Once you find x:
x - 3 cm = final answer

no trig needed
this has to be done without trig
@burnt relic have you done sin cos tan yet
I like my trig 
liek sin cos tan
or do you know what they mean
i know
oh ok use his method then
similar 📐
its just that our teacher wanted us to do it with scale factor
To forget u h
@serene field but that requires a calculator right
If you're good enough with ratios, you don't need a calculator 🤔
cuz you need to calculate t=arccos(3/sqrt13)
gl with that
Ok i got one more
A plane takes off in a straight line and travels
along this line for 10 s, when it reaches a height
of 300 m. If the plane is travelling at 60 m/s, at
what angle is the plane ascending?
would i divide 300 by 10 to get the m/s to make all units the same?
it's still the same problem
however you should see how far it travels by using its speed
$$\frac{60\text{ m}}{\text{s}}\cdot\frac{10\text{ s}}{}$$
MiracleMan:
be sure to write units so you can cancel them correctly
Surveyors need to determine the height of a hill. They set up a laser measuring device on a pole that is 1m tall and shine the laser toward the top of a second pole, which is 1.6m tall. Then they adjust the distance between the two poles until the laser hits the top of the longer pole and the top of the hill. The 1.6m pole is 415m from the centre of the hill. The 2 poles are 12m apart. Find the height of the hill.
final q for the day if any1 can help
draw the picture
then draw a triangle eith the base starting from the top of the first pole
ok
similar triangles and all that stuff
i propose we delete trigs from the entirety of human knowledge
because they are hard
,tex just use pyt similarty and find AD and then DB
ISIPINI:
Hey wut ?
the triangles are similar for obvious reasons 😄
similarty implies taht AB/AD = BC / DE
That's what I do
so its correct ...
Just proved it with trig
aah u were the one helping ;D
😟
Does anyone understand Proofs?
But can you prove that?
i just need someone to explain ASA AAS and all the other ones
Those are generally considered postulates in elementary geometry, no?
I believe so but im in high school
That's what I meant. Between algebra last year and algebra ii/trig next year, right?
algebra 2 next year yes
OK, so in your level of geometry, I'm pretty sure SSS, ASA, and so on are considered postulates, no?
you can prove similar triangle, then use prop of similar triangles
Can someone explain to me how I go about solving question seven from above?
Have you learned transversals yet?
can anyone help me discover the third coterminal angle of angle 67?
What do you have so far @kind wagon
@split laurel 427, 787
hmm cheers @split laurel
anytime
what
wat
ew geometry
no geometry is fun. that's true, no part of geometry is fun
And so began the great geometry war of discord
Can someone help me with this question please
The graph of y=aSinb theta has a maximum value of 5 and a period of 45 degrees What are the values of a and B
since sin x has a maximum value of 1
max(a sin bx) = 5 implies that a = 5
the period is 45
45 degrees is pi/4
and regular sine has period 2pi
sin(kx) has period 2pi/k
so you can figure out b from that
Oh i see thanks
prove that ADB and BEA are similar triangles
ADF?
ADB sorry
what do i need to research to solve these 3 problems ? https://www.dropbox.com/s/3bwgn4iln0zify5/wordpad_2018-12-21_14-52-26.png?dl=0
@lapis geyser sin function is odd and cos is even
Hmm you can use Khan Academy
ok thanks
@lapis geyser Paul's notes
In this chapter we give a brief review of selected topics from Algebra and Trig that are vital to surviving a Calculus course. Included are Functions, Trig Functions, Solving Trig Equations and Equations, Exponential/Logarithm Functions and Solving Exponential/Logarithm Equa...
Very useful trig
oooooh that looks like gold, thanks @sharp nymph
Avoid posting in multiple channels
how would i let this rotate
could you be more specific?
like lets say i would want rotate this "T" about 50 degree how would i do that
by the use of a rotation matrix
where the new coordinates (x',y') are given by multiplying the rotation matrix on the right by the original coordinates (x,y)
Ya x=4cm
thanks
@mystic shadow when doing only cos for x and sin for y it also works
no it doesn't
if you can't do matrix multiplication, the full equations are:
x'=xcos(theta)-ysin(theta)
y'=xsin(theta)+ycos(theta)
you're just breaking the vector into its x and y components
not rotating it like your original request was
hope you figure it out bbl
Yep
if i know a position vector OA and another position vector OB
how do i know AB?
do i just add them
ah i see
Two things give most of these questions away
sin(-x) = -sin(x) (sin is odd)
cos(-x) = -cos(x) (cos is even)
@lapis geyser
cos(-x)=cos(x)
i never learned Trigonometry, learning it from scratch, and homework is due today, totally lost atm lol
any Khan series that explains the picture i linked. Pressed for time
after homework is due im going to go back over it again and study it further
This trigonometry video tutorial explains how to use even and odd trigonometric identities to evaluate sine, cosine, and tangent trig functions. This video c...
thank you very much both of you
dudesmen
if the triangle with vertices X(3, 5) , Y(4, 2), Z(-5, a)
is right angled at Y
how can we find 'a'
?
pythagoras will certainly do the trick
how ?
emeric75:
right
then ?
so i get the distance between the sides ?
and work my way backwards with the distance "algorithm"
?
ya, and you'll get an equation for a
the distance rule is as i know it something like this:
$$sqrroot((x2-x1)^2+(y2-y1)^2)$$
Sentoss:
yea get the lengths of the sides using dat formula
and plug them inside that pythagoras thing
let me try and get back to you
bro
all i got is
XY = sqr10
XZ = sqr(64+(a-5)^2)
YZ = sqr(81+(a-2)^2)
where can i go from here
yea seems right
ok so let's plug those things inside that pythagora's equation (we need those distances to verify pythagoras if we want XYZ to be a right triangle)
XZ= sqr(YZ^2 + XY^2)
$$XY^2 + YZ^2 = XZ^2 \iff 10 + 81 + (a-2)^2 = 64 + (a-5)^2$$
(tbh just leave the squares)
there is no "(a-1)^2"
typo'd
emeric75:
"(a-2)^2" is the correct one
np
so i should move the 64 to the left and the (a-2)^2 to the right
ya
ok
ok so
moving our variables on one side and the constants on the other one
$$91-64 = (a-5)^2 - (a-2)^2$$
emeric75:
Sentoss:
expanding those squares :/
Sentoss:
wow!!!
$$(a-b)^2 = (a-b)(a-b) = aa -ab - ba +bb = \boxed{a^2 -2ab+b^2}$$
emeric75:
that's distributing
(that's what i just did?)
so what should i do again ?
- memorize it /or/ 2. remember that (a-b)^2 = (a-b)(a-b) by definition of squaring and expand
Sentoss:
right ?
emeric75:
then expand those
Sentoss:
didn't think i'd be here for basic algebra but i am dommed to help you now
$$(a+b)\cdot(c+d) = a(c+d) + b(c+d) = ac + ad + bc +bd$$
emeric75:
bro ?
so for example if we take $(a-2)(a-2)$
emeric75:
$(a-2)(a-2) = a(a-2) - 2(a-2) = a^2 - 2a -2a + 4 = a^2 -4a +4$
emeric75:
Distributive property
a * (b + c) = ab + ac
In this case, he expanded it into:
(a + b) * (c + d) = a * (c + d) + b * (c + d)
Well, here's an example:
4 * (5 + 6) = 4 * 11 = 44, yes?
Well, with the distributive property, this becomes
yea i think so
4 * (5 + 6) = 4 * 5 + 4 * 6
= 20 + 24
= 44
You basically multiply the stuff outside the brackets with everything inside
but here we have 2 brackets and there is no outside
so basically
i think it'll be something like
$$-27 = a(a-2) - 2(a-2) - a(a-5) - 5(a-5)$$
Sentoss:
What was the original?
$$-27 = (a-2) (a-2) - (a-5) (a-5)$$
Sentoss:
Sentoss:
$$-27=a(a-2)-2(a-2)-a(a-5)+5(a-5)$$
Hello World:
since -(a - 5)^2 = -1(a - 5)(a - 5)
oh that's why the +
yep
but still why not the same with the 2(a-2) ?
Because it's (a - 2)^2, not -(a - 2)^2
NOOOOOOOOO!!!!
i can't expand more than that
like this is the best i can do
so...
a(a-2) will be a^2*-2a ?
Sentoss:
=pup -27 = (a-2)^2 - (a-5)^2
-27 = (a - 2)(a - 2) - (a - 5)(a - 5)
-27 = a(a - 2) - 2(a - 2) - a(a - 5) + 5(a - 5)
-27 = a^2 - 2a - 2a + 4 - a^2 + 5a + 5a - 25
-27 = 6a -21
-27 + 21 = 6a
-6 = 6a
-1 = a
Was your process anywhere close to that?
-27=(a - 2 + a - 5)(a - 2 - a + 5)
-27=(2a - 7)3
-9=2a - 7
-2=2a
-1=a
shorter version
That works, but i was talking to him about the distributive property above, so it was only fair to solve it the same way
absolutly aweful diagram here but this is the problem i have been presented with and i have no clue how to find the length of x or if it is even possible
try making triangles with the center of the circles
lol
ty
np
which triangle did you make?
lemme make a new better diagram
there's a better triangle you can draw i think
that vertical side
how about you extend it further?
so it goes down to the centre of the bottom circle
no
well the vertical one is 1 + x right?
yes
top horizontal is 1 right?
yes
im not sure what radii is
2 radius length
oh yeah
so 2 * 1 = 2 right?
yes
and then you can just pythagorean theorem from here
alright thank you
Would I be right in saying that given 2D vectors A and B, if (A + B)'s x and y components are both not zero, A * q added to B * p can be equal to any 2D vector by changing values of q and p (allowing q and p to be negative, zero or positive)? If that makes sense to you.
what if A and B are collinear ? 
if (A + B) has non-zero x and y components then wouldn't they inherently be not collinear?
or am I understanding you wrong
A=(1,1) / B=(2,2) they're collinear right?
ah I see, I only thought of them pointing in opposite directions. Good call
So would A + B and A - B and B - A all have to have non-zero x and y components?
well you'd need A != kB for any k in R
(which is much more cases than you can write in a "A+B A-B" way)
non colinear one another again but ye
That's great, thank you. I'm working on a programming project and want to balance a mass on thrusters automatically, or at least attempt to get as close to it as possible.
Maybe a physics server might be a better place for assistance with the rest of it though
oof good lucks : if you wanna go further about this vectory idea just take any lin alg book
yeah physics would be better ^^
Thanks once again, I appreciate the help 😃 I'll keep at it


You want to look into control theory for holding a state
Feel free to ask anything about control here or in the physics server!
Currently I'm at the point where I have the torque that each thruster provides and can also get the change in angular velocity for firing it for one physics update (1/50s), my approach is to give each thruster a factor from 0 to 1 based on how (inversely-)"useful" it is to correcting the error. So the more torque a thruster has (if it is acting in the correct direction) the more useful it is therefore it needs to be at a lesser throttle % (factor) than a weaker thruster to generate the same torque on the centre of mass.
If I'm thinking it through right, assigning each thruster a factor based on the amount and direction of torque produced so that the torque * factor are equal for all thrusters should produce a balanced system.
My problem is calculating the usefulness properly. I tried a couple approaches and some worked a bit but not fully. Best I had is a stable balancing system but it would constantly switch between two engines firing at full power and two being off, so whenever it would lean any amount to the left of centre the right engines would turn off and vice versa. I tried fixing it by making the error-based factor smaller the closer to the correct orientation the object was, so if you were 45 degrees off the engines would try hard to correct it but as you approached the correct orientation the factor would fade towards one which simply has all the thrusters balanced proportional to how much torque they produced. I messed up somewhere and couldn't get it right though and anyway it felt like an improper cheaty solution.
How would you approach a problem like this:
vectors t0 through tn are known (torque from thrusters)
coefficients c0 through cn are unknown (factors or throttle, but for the sake of this they are not constrained to 0.0-1.0, they can be any real number)
error to correct e is known
find values of c0 to cn where (c0t0 + c1t1 + c2t2 + .. + cntn) is as close to e as is possible
there would be multiple answers I assume and that makes it even harder. Is there a better approach to something like that? Where would I find info on this?
Something like
Yue:
That?
yes, although that wouldn't cover edge cases where they can not be equal to e and instead you'd have to get the closest approach
Would they need to be broken down into simultaneous linear equations recursively? Ignoring the edge cases for now
Honestly, I have no idea. A linear system is probably the way I'd attempt to solve this. Maybe one of the helpers can solve this better than I know how. 🤔
That's grand, I'll look into the different methods. Thanks 😃
A lad on a computer science discord said that it's a least squares problem but I can't see any way to use the method for my problem although I do see some similarities
Now that I think about it, I'm pretty sure I can't break it down into linear equations because even if it was 2(c0) + 3(c1) = 4, there are infinitely many values for c0 and c1 that would work. The only values I actually want are where |c0-c1| is the smallest it can be.
Maybe I should think of it as a line on a n+1 dimensional graph
If that would get me anywhere closer to an answer? Probably not but worth to think on
e.g. say error correction value e is the y axis, c0 is x axis and c1 is z axis. Using the previous example, y = 4 so equation is 2x + 3z = 4.
Okay, so what is this thing? Are we in 2D? A plank with two forces acting on each side?
My ideal result would be where x and z are the closest and I know it's easy af to calculate that but it's late and I can't put my finger on it lol
It's 3D
Imagine a hovercraft with engines
Four of them?
for example 1 each corner so 4 engines
yea
And ideal scenario would be all 4 at 100%
but a possibility would be 2 corner engines at 100 and 2 others at 0
and it would still technically be stable
so I guess total % should be max if I'm thinking straight
either that or all %s should be as similar as possible
I'm leaning towards the latter actually
Also important to note is that in this example the engines are all pointing straight down so it's more 2D-ish but that may not always be the case
I imagine you're trying to control two things, the height of the hovercraft and the angle at which it hovers
3D manouvering is tough, lol.
The height would be easier I assume
get the angle right then adjust total thrust
so getting the angle stable is the main challenge
You can do both at once with an ideal system
How is that?
Well, how much do you know? Understand calculus?
Not really just the overall idea of it, not in uni yet so just doing this as a hobby out of interest
I have the vague idea of getting the slope of a curve by being more and more precise with an average over a time, or however you would put it. But in-depth not at all
In physics, velocity is the slope of displacement, and acceleration is the slope of velocity
You also have F = ma, so you can control "a" directly with thrusters.
So you have full control over acceleration, but you want control over displacement.
So I imagine there'd be a most efficient way of changing s by controlling a, since if you just go full on until you overshoot you're gonna have to backtrack etc?
Exactly, you're calling it. And, it's not a crazy simple problem
And how does that play into angle?
All the while, you have to control the angle
You have Newton's second law of rotation.
τ = Iα
τ, or torque, is controlled by the thrusters, so you can control acceleration of angle, or α
Once again, you want to control the angle, but you have control of the second derivative
ah, I see
So I've said a lot but haven't said much for results
You should have some I from the physics simulation, so you should know how fast it starts to rotate, given a thruster is on
Yeah, I can get the angular acceleration (if that's the word) for firing it for 1/50th of a second (one physics frame), I assume that dealing in discrete units of time simplifies things as well compared to a real-world simulation.
I could be wrong through since that may only be the case if you are doing compounding calculations (or however they're called)
Run one thruster for two "cycles", how much does the angle change in each one?
angle or angular velocity?
Angular velocity changes almost same amount as predicted by the code, so for x axis it's about 7.5 deg/s per cycle. Angle itself is more difficult because the whole thing flies off at an awkward rotation and direction so the axes get messed up, since I know ang vel around local axes but the rotation itself is shown about the global axes. I use unity and the physics tend to be a bit wonky but realistically implemented. My money is on local x angle being 0 at beginning, then 1/50 of 7.5, then another 7.5 is added to vel so 1/50 of 15 added to angle so total after 2nd update would be 7.5/50 + 15/50 = 22.5/50
Phys frame 0: angle 0 vel 0
1: angle 7.5 vel 7.5
2: angle 22.5 vel 15
I'd have to do a more in depth test for 100% accurate results, I through that one together sloppily since it's 3am so I'll be back at it tomorrow. Thanks a lot for the insight btw, sorry about running off partway through but I shouldn't be messing up my sleep more than already lol. I'll check back the next day
Before I forget though, if I wasn't dealing with vectors but instead scalars, having an equation e = c0t0 + c1t1 etc. Wouldn't be hard to get optimal values for. I believe it would be:
optimal coefficient = error correction amount * (1 - (torque/total torque))
including signs and so on, not absolute values. Ofc if total torque cancelled out by default then it would be dividing by zero, so I'd have to have a failsafe for that and just set them all to one. That's besides the point though. My problem is that in 1D, A = kB no matter what, for real numbers. In 3D though, it's much more complex. Also torque can be in the wrong direction and in 3D that is usually not solveable by scaling, hence why my initial question where it was deducted that you'd need 3 vectors which would not be collinear to have full control over where they point if scaled independently and summed.
Hello!
Question 1: So you have an 8 inch x 8 inch standard issue chessboard. You are also provided with unlimited 2 inch x 1 inch rectangles (dominoes).
Can you tile the chessboard with the rectangles with no overlap and no extra rectangles nor parts of rectangles hanging off the playable part of the chessboard?
SPOILER
Turns out the answer is yes. Just tile each row with four 2 x 1 rectangles end to end.
The following a famous problem ...
Question 2: So you have an 8 inch x 8 inch standard issue chessboard AND you remove 1 pair of diagonally opposite corners. You are also provided with unlimited 2 inch x 1 inch rectangles (dominoes).
Now, can you tile THIS chessboard (with corners removed) with the rectangles with no overlap and no extra rectangles nor parts of rectangles hanging off the playable part of the chessboard?
SPOILER
It turns out ... no :(
But, of course, in math you need proof.
And this turns out to be a tricky proof to come up with, but very simple to understand.
Each rectangle MUST cover two squares: one square of each color.
Since the two removed squares are the same color (WLOG black) you have 32 white and 30 black squares left over. This cannot be tiled by 2 x 1 rectangles.
But then one has to ask ... Question 3: What about other shapes? Maybe Tetris shapes?
Of course you can't tile an 8 x 8 chessboard with two corners removed and have it be tiled by pieces with an area of 4. That's 62 for the leftover area and 4 doesn't divide 62. 😃
Question 4: But what if I said you can remove Any 4 squares of the same color? Or any 4 squares where 3 are of one color and 1 is of the other? We solved the problem of not having the whole area being divisible by the area of the piece.
It turns out that all of these Tetris pieces:
++ ++ ++ +++ +
++ ++ ++++ ++ + +++
... must also cover exactly 2 white and exactly 2 black squares.
This means that not just any one of the above Tetris pieces but Any Combination of pieces cannot tile any board with unequal white and black squares. The only odd piece out is the T-shaped piece. But I'll leave that for further study.
Hey guys what is the best book for trig, a book.that explains concepts, and gives examples, easy to understand. Overall a great book to learn trig
Take the derivative
So do I have just have to draw it and explain right?
yeah I guess
for AA postulate, say that:
- the sum of angle measures in a triangle is 180 degrees
- say there are three angles in two triangles: in triangle ABC, There are angles 1 2 and 3 and in triangle DEF there are angles 4 5 and 6
- given angle 1 is congruent to angle 4 and angle 2 is congruent to angle 5, angle 3 is congruent to angle 6 using the difference of 180 - (angle 1 + angle 2) = 180 - (angle 4 + angle 5)
- since this is AAA, the ratios of the corresponding sides in each triangle
- in conclusion, AA postulate is an extension of AAA, proving that two triangles are similar
a. since ADC is a right angle at D, ACD (angle) = angle B (since they both equal 90-A) therefore (by AAA similarity) ADC is similar to ABC, same thing for CBD but this time it's angle DCB=90-B (aka same as A)
hopefully this helps (sorry for the amateur proof writing)
Standard form of a circle is (x-h)^2+(y-k)^2=r^2,let's say center of the circle is at 3,-2. Now its (x-3)^2+(y+2)^2=81, for what type of question would they ask me to plus in x and y Into there and what does that give me?
I'm so confused what
Are y'all talking to me?
@keen aspen since you really helped me.last time can you help me with the picture above
can someone Mathbot this for me please?
no
all the lines that you can make out
no
use excel --> save delimited --> get rid of all commas ....
Help...
Which are you having trouble with? Any definitions you're not good on?
