Simplify be reducing to a single term :
`cos 5 theta cos 2 theta - sin 5 theta sin 2 theta.`

Simplify be reducing to a single term : cos (theta + alpha ) cos ( theta - alpha ) - sin ( theta + alpha ) sin (theta - alpha).

cos 20 theta in terms of sin 5 theta .

Solve cos 4 theta+ sin 5 theta=2 .

Solve : 3-2 cos theta -4 sin theta - cos 2theta+sin 2theta=0 .

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

1 + (cos 2 theta + cos 6 theta)/(cos 4 theta) = (sin 3 theta)/(sin theta).

(1+sin 2theta+cos 2theta)/(1+sin2 theta-cos 2 theta) =

Find (dy)/(dx) if x= 3 cos theta - cos 2theta and y= sin theta - sin 2theta.

Solve cos4theta+sin5theta=2

(sin theta + sin 2 theta)/( 1 + cos theta + cos 2 theta) = tan theta.