Question

if x-1/x=4 find the value of x^3-1/x^3

Answer 1

(x-1/x)^3= 4^3
=x^3-1/x^3-3x*1/x(x-1/x) =64
=x^3-1/x^3-3(x-1/x)=64
x^3-1/x^3=64+3(x-1/x)
=64+3*4
x^3-1/x^3 =76(answer)