Question

If x-1/x=2,find x^4+1/x^4

Answer 1

x-1/x=2
then
(x-1/x)^2=2^2
x^2+1/x^2-2=4[as (a+b)^2=a^2+b^2-2ab]
x^2+1/X^2=6[4+2]
(x^2+1/x^2 )^2=6^2
x^4+1/X^4+2=36.
X^4+1/X^4=36-2=34