Question

x+1/x=4 Find the value of this

x^3+1/x^3

Answer 1

(x+1/x) = 4 -------(1)

On cubing both sides, we get

x^3 +1/x^3 + 3x*1/x (x+1/x) = 64

=> x^3 + 1/x^3 +3*4 = 64

=> x^3 +1/x^3 +12 = 64

=> x^3 + 1/x^3 = 52