If `costheta=cosalphacosbeta` , prove that `t a n(theta+alpha)/2t a n(theta-alpha)/2=t a n^2beta/2` .

If cos theta=(cos alpha-cos beta)/(1-cos alpha cos beta), prove that tan theta/2=+-tan alpha/2 cot beta/2.

Prove that: t a nalpha+2tan2alpha+4tan4alpha+8cot8alpha=cotalpha

If tan beta=cos theta tan alpha , then prove that tan^(2)""(theta)/(2)=(sin(alpha-beta))/(sin(alpha+beta)) .

Prove that cos(alpha+beta )=cosalphacosbeta-sinalphasinbeta

If cos (theta - alpha) = a and sin(theta - beta) = b (0 lt theta - alpha, theta - beta lt pi//2) , then prove that cos^(2) (alpha - beta) + 2ab sin (alpha - beta) = a^(2) + b^(2)

If sin theta = 3 sin ( theta + 2 alpha) , then the value of tan (theta + alpha ) + 2 tan alpha is

By vector method, prove that cos (alpha+Beta) = cosalphacosBeta-sinalphasinBeta .

If t a nbeta=(nsinalphacosalpha)/(1-nsin^2alpha) , show that tan(alpha-beta)=(1-n)t a nalphadot

If alpha=^m C_2,t h e n^(alpha)C_2 is equal to

If alpha and beta are the two different roots of equations alpha cos theta+b sin theta=c , prove that (a) tan (alpha-beta)=(2ab)/(a^(2)-b^(2)) (b) cos(alpha+beta)=(a^(2)-b^(2))/(a^(2)+b^(2))