Anonymous wrote:If xy=1 what is the value of (2(x+y)^2)/(2(x-y)^2)?
This one is from Gprep
Ans: 16
We know that 2^a/2^b = 2^(a-b), (x+y)^2= x^2 + 2xy + y^2 and (x-y)^2 = x^2-2xy+y^2
So 2^(x+y)^2/2^(x-y)^2 = 2^((x+y)^2-(x-y)^2) = 2^(4xy), but xy=1 so 2^(4xy) = 2^4 = 16.
Regards
