Question

If x + 1/ x =a  then x^2 + 1/x^2 =

Answer 1

x + 1 / x = a
Square both side
( x + 1 / x )^2 = a^2
x^2 + (1/x)^2 + 2 . x . 1 / x = a^2
x^2 + (1/x)^2 + 2 = a^2
x^2 + 1/x^2 = a^2 - 2