Prove that:
`(tan(alpha-beta)+tan(beta-lambda)+tan(lambda-alpha) = tan(alpha-beta)tan(beta-lambda)tan(lambda-alpha)`

If alpha + beta + gamma = pi , show that : tan (beta+gamma-alpha) + tan (gamma+alpha-beta) + tan (alpha+beta-gamma) = tan (beta+gamma-alpha) tan (gamma+alpha-beta) tan (alpha+beta-gamma)

Prove that: tan(alpha+beta)tan(alpha-beta)=(sin^2 alpha-sin^2 beta)/(cos^2 alpha-sin^2 beta)

Sum the series tan alpha tan (alpha+beta)+tan(alpha+beta)+tan(alpha+2beta)+tan(alpha+2beta)tan(alpha+3beta)+… to n terms

Prove that: tan^(-1){(cos2alphasec2beta+cos2betasec2alpha)/2}=tan^(-1){tan^2(alpha+beta)tan^2(alpha-beta)}+tan^(-1)1

If alpha+beta+gamma=2pi, then (a) tan(alpha/2)+tan(beta/2)+tan(gamma/2)=tan(alpha/2)tan(beta/2)tan(gamma/2) (b) tan(alpha/2)tan(beta/2)+tan(beta/2)tan(gamma/2)+tan(gamma/2)tan(alpha/2)=1 (c) tan(alpha/2)+tan(beta/2)+tan(gamma/2)=-tan(alpha/2)tan(beta/2)tan(gamma/2) (d)none of these

if tan alpha = 2tanbeta show that (sin(alpha+beta))/(sin(alpha-beta)) = 3

cos(alpha+beta)+sin(alpha-beta)=0"and"tanbeta=1/2009 ,find tan(alpha)

(sinalpha+sinbeta-sin(alpha+beta))/(sinalpha+sinbeta+sin(alpha+beta))=tan(alpha/2)tan(beta/2)

If cosx-sinalphacotbetasinx=cosa , then the value of tan(x/2) is (a) -tan(alpha/2)cot(beta/2) (b) tan(alpha/2)tan(beta/2) (c) -cot((alphabeta)/2)tan(beta/2) (d) cot(alpha/2)cot(beta/2)

(1+tan alpha tan beta)^2 + (tan alpha - tan beta)^2 =