" 16."cos theta-sin theta=cos alpha-sin alpha

Prove that cos 4theta–cos 4alpha = 8(cos theta-cos alpha)(cos theta+ cos alpha )(cos theta -sin alpha)(cos theta+sin alpha)

If tan theta=(cos alpha-sin alpha)/(cos alpha+sin alpha) and theta is acute then theta+alpha=

If tan alpha=(sin theta-cos theta)/(sin theta+cos theta) then sin alpha

If tan theta=(sin alpha- cos alpha)/(sin alpha+cos alpha) , then:

If tan theta=(sin alpha- cos alpha)/(sin alpha+cos alpha) , then

If tan theta=(sin alpha- cos alpha)/(sin alpha+cos alpha) , then:

If tan theta=(sin alpha-cos alpha)/(sin alpha+cos alpha), prove that 2cos^(2)theta=1+sin2 alpha

If tan theta=(sin alpha-cos alpha)/(sin alpha+cos alpha) ,then theta is