00:01
Here on this problem, we want to convert r equals a sine 3 theta into retangular coordinates.
00:10
Now first to note is our identity for the sine of 3 theta is 4 sine theta, cosine squared theta, minus the sign of theta.
00:23
And that's your identity for the sign of 3 theta.
00:28
So this tells us that r is equal to 4a sine theta, cosine squared theta, minus a sine theta.
00:43
Again, that just comes from subbing in that identity there for the sign of 3 theta.
00:49
Now i'm going to multiply everything here by r cubed.
00:53
And so here on the left, this gives me r to the fourth.
00:56
On the right, i have 4a.
00:57
I'm only going to put one of the r's i multiplied in with the sine theta.
01:00
So i have r sine theta.
01:02
I'm going to put the other two with the cosine square root of theta.
01:07
And just broke it apart there.
01:09
Then i have minus a r sine theta...