00:01
So we're looking for d t d r, which is going to be equal to d t times d x times d x, d .r, which will be 2xx minus y cubed times cosine theta, plus x squared minus 3x y squared times high in theta.
00:30
These two terms over here is d -d -y times d -y -d -r.
00:37
Then we'll go ahead and do our substitutions of x's and y's into using vs.
00:42
Sorry, our r's and theta's into x and y.
00:47
So that will give us 2r squared, cosine squared, theta, sine -theta, minus r - cubed, cosine theta, sine -cubed theta, plus r -squined theta, plus r -squared.
01:03
Cosine squared theta, sine -squared theta, minus 3r -quipped, cosine -theta, sine -cubed theta.
01:25
And then we'll go ahead and combine like terms...