Question

cos theta -cos theta sin^2 theta. I know the answer is cos ^3 theta but i'm not sure how i got the answer

Answer 1

\[\cos\theta-\cos\theta\sin^2\theta=\cos\theta\left(1-\sin^2\theta\right)\]If it's unclear what happened there, think of the left hand side as
\[a-ab^2=a(1-b^2)\]
Now, what do you know about \(1-\sin^2\theta\)?

Answer 2

1 - sin^2 theta = cos^2 theta

Answer 3

cos cos theta ( 1 - sin^2 theta) = cos^3 theta

Answer 4

- ignore the first cos!!