/sci/ - Science & Math

[Anonymous No.7515974]

Anyone care to help? I'm in calc 2 and my girlfriend is in this algebra class and usually I teacher her the subjects instead of her going to class and now she got this problem I don't know how to approach.

[Anonymous No.7515978]

>>7515974
retard

[Anonymous No.7515984]

>>7515974
did you know that the sum of the squares of the lengths of the short sides in a right-angled triangle is equal to the square of the hypotenuse? it's called dolan's theorem, you can use that

[Anonymous No.7516000]

>>7515978
I feel retarded lmao I just learned all the integration techniques and now I go to this and feel stupid. Oh well I am a bio major.

[Anonymous No.7516001]

>>7515984
icee watu did theer

[Anonymous No.7516009]

>>7515974
>I teacher her the subjects instead of her going to class

WHY EVEN REGISTER? If she can learn it outside of class, she should and test out of it.

To answer your question: By definition of a circle, all points (x,y) on it are distance r away from the center (h,k). By the euclidean distance formula this is √[(x-h)^2+(y-k)^2]=r. Square both sides to remove the root (root are mess m'kay).

[Anonymous No.7516014]

>>7515974
the squared distance between any two points in a plane is given by the equation
<span class="math">
(x_2 - x_1)^2 + (y_2 - y_1)^2 = d^2
[/spoiler]

This is because any two points could be representative of two vertices of a triangle, with the hypotenuse being the distance, and the legs being the change in x and change in y.
In this case, we are trying to find a general form for the x and y of any point on the circle, which is defined as the locus of all points equidistant from a center point (h,k).
Essentially what this means is that we know the distance from the center (r) and the center's location <div class="math"> x_1</div> and <div class="math"> y_1 </div>.
Substituting in the known values,
<span class="math">
(x_2 - x_1) ^2 + (y_2 - y_1)^2 = d^2 = r^2 = (x - h)^2 + (y - k)^2
[/spoiler]
QED, though not rigorously.
polite sage.

[Anonymous No.7516019]

>>7516009
Her professor is a Chinese adjunct and she can't understand her very well. I'm pretty good at teaching math ore calculus and under, I was a tutor for high school students. But any of these proof problems I can't do very well. I'm not a math major and all the professors I've ever had never gave us problems that require thought. But thank you.

[Anonymous No.7517002]

>>7516009
>m'kay
Fucking stop this. Seriously, fucking stop saying this. Stop typing this. It's almost as bad as

>'tis
>m'lady

It's fucking obnoxious sounding, and the joke stopped being funny almost 14 years ago.

[Anonymous No.7517107]

>>7515984
Is there also one called Gooby's theorem.

[Anonymous No.7517191]

>>7515974
Are American universities really this easy?

>>7516014
Did ye use LaTeX to write that?

[Anonymous No.7517193]

>>7515974

how the FUCK DO YOU DO THIS
THIS MAKES NO SENSE
THEY DONT GIVE YOU ANYTHING TO WORK WITH

[Anonymous No.7517220]

Use Barnet's Formula: x^2 + y^2 + r^2

[Anonymous No.7517222]

>>7517220
Also, it has to do with triangles and shit.

[Anonymous No.7517234]

>>7517191
This would be LaTex

\[ \left( {x}_{2}-{x}_{1} \right) ^2 + \left( {y}_2 - {y}_1 \right) ^2 = d^2 = r^2 = \left( {x}-{h}\right)^2 + \left( {y}-{k} \right)^2 \]

>LaTex ftw

[Anonymous No.7517252]

>>7515974
your dock setup sucks ass

[Anonymous No.7517255]

Look at picture. Take your old greek dude who said triangles are cool as long as they have a hippopotamus. Apply his formula in a coordinate system. Do maths.

[Anonymous No.7517257]

employ the distance formula and the pythagorean theorem.

[Anonymous No.7517260]

>>7515974
assign r an arbitrary value. let's say 6
from there find the circumperence, volume, etc.
plot based on the values of your variables in the equation listed in the problem.

[Anonymous No.7517263]

>>7517234