[" I Example "68." If "cos alpha=(1)/(2)(x+(1)/(x)),cos beta=(1)/(2)(y+(1)/(y))],[" then evaluate "cos(alpha-beta)]

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

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

If 2 cos alpha = x + (1)/(x) and 2 cos beta = y + (1)/(y) , show that (x)/(y) + (y)/(x) = 2 cos( alpha - beta)

If 2 cos alpha = x + (1)/(x) and 2 cos beta = y + (1)/(y) , show that xy - (1)/(xy) = 2i sin (alpha - beta)

sin alpha+sin beta=(1)/(4) and cos alpha+cos beta=(1)/(3) The value of cos(alpha+beta) is

sin alpha+sin beta=(1)/(4) and cos alpha+cos beta=(1)/(3) The value of cos(alpha+beta) is

If alpha=sin^(-1)(cos(sin^(-1)x)) and beta=cos^(-1)(sin(cos^(-1)x)) then find tan alpha.tan beta

If sin alpha=1/2 and cos beta=1/2 then alpha+beta=

If x+1/x=2cos alpha,y+1/y=2cos beta, then xy+(1)/(xy)=

If 2 cos alpha = x + (1)/(x) and 2 cos beta = y + (1)/(y) , show that x^(m) y^(n) + (1)/(x^(m)y^(n)) = 2 cos (m alpha + n beta)