The sides of triangle are in `A.P.` and the greatet and least angle are `theta and phi` : prove that `4(1-costheta)(1-cosphi)=costheta+cosphi`

The sides of triangle are in A.P. and the greatet and least angle are theta and phi: prove that 4(1-cos theta)(1-cos phi)=cos theta+cos phi

If the sides of a triangle are in A.P. and the greater and the least angles are theta and phi respectively, then show that, 4(1-cos theta)(1-cos phi) = cos theta +cos phi

Prove that sintheta/(1-costheta)=cosectheta+cot theta

Prove that : (1-costheta)(1+costheta)(1+cot^(2)theta)=1

Prove that : (1-costheta)(1+costheta)(1+cot^(2)theta)=1

Prove that : sqrt((1+costheta)/(1-costheta))="cosec"theta+cottheta

Prove that : sqrt((1+costheta)/(1-costheta))="cosec"theta+cottheta

The sides of a triangle are in A.P. and the greatest angle exceeds the least by 90^@ prove that the sides are proportional to sqrt7+1,sqrt7 and sqrt7-1

Prove that : (sin theta)/(1 - costheta) = cosec theta + cot theta

Prove that : (sin theta)/(1 - costheta) = cosec theta + cot theta