यदि `f(x)=(2^(x)+2^(-x))/(2)`, तब `f(x+y).f(x-y)=`

If f(x)=(2^(x)+2^(-x))/(2) , then f(x+y).f(x-y) is equal to

If f(x)=(2^(x)+2^(-x))/(2), then f(x+y)f(x-y) is equals to (1)/(2){f(2x)+f(2y)}(b)(1)/(2){f(2x)-f(2y)}(c)(1)/(4){f(2x)+f(2y)}(1)/(4){f(2x)-f(2y)}

If f(x)=(a^(x)+a^(-x))/(2) and f(x+y)+f(x-y)=kf(x)f(y) then k=

If the function f: R to R defined by f(x)=(3^(x)+3^(-x))/(2) , then S.T f(x+y)+f(x-y)=2f(x)f(y) .

If f(x)=(a^(x))+a^(-x)/(2) and f(x+y) +f(x-y)=Kf(x) f(y) , then the value of K.

If f(x)=(2^x+2^(-x))/2 , then f(x+y)f(x-y) is equals to (a) 1/2{f(2x)+f(2y)} (b) 1/2{f(2x)-f(2y)} (c) 1/4{f(2x)+f(2y)} 1/4{f(2x)-f(2y)}

If f(x)=(2^x+2^-x)/2 , then f(x+y) f(x-y) is equal to:

Given the function f (x) =(a ^(x) + a ^(-x))/(2), a gt 2, then f (x+y) + f(x -y) =