If `cosalpha = 3/5 and cosbeta=5/13,` then `cos^2\ (alpha-beta)/2=`

If cos alpha = (3)/(5) , cos beta =(5)/(13) , "then " cos^(2) ((alpha - beta )/(2))=

If cosalpha=1/2(x+1/x) cosbeta=1/2(y+1/y) then cos(alpha-beta) is equal to

If cos alpha =(3)/(5) and cos beta =(5)/(13) and alpha, beta are acute angles, then prove that (a) sin ^(2)((alpha-beta)/(2))=(1)/(65) and (b) cos ^(2)((alpha+beta)/(2))=(16)/(65)

If cos alpha=3/5 and cos beta = 5/13 and alpha , beta are acute angles , then prove that cos^(2)((alpha+beta)/2)=16/65

If cosalpha=(3)/(5),cosbeta=(5)/(13),0ltalpha,betalt(pi)/(2) then find the value of sin^(2)((alpha-beta)/(2))andcos^(2)((alpha-beta)/(2)) .

If cosalpha+cosbeta=0=sinalpha+sinbeta , then cos2alpha+cos2beta=?

If cosalpha+cosbeta=1/3 and sinalpha+sinbeta=1/4 prove that cos(alpha-beta)/2=+-5/24

If cosalpha=cosbeta , then alpha+beta= ____

IF cos (alpha +beta )=(5)/(13) and cos (alpha - beta )=(4)/(5), then find the value of tan 2 beta .

If cosalpha+cosbeta=0=sinalpha+sinbeta" then "cos2alpha+cos2beta