Question

If x - 1 by x equal 4, then evalates x square 1 by x square and x cubic 1 by x cubic

Answer 1

Answer:

Answer is given according to the correct question.

x - 1/x = 4

Square on both sides:

= > ( x - 1/x )^2 = 4^2

= > x^2 + 1/x^2 - 2(x*1/x) = 16

= > x^2 + 1/x^2 - 2(1) = 16

= > x^2 + 1/x^2 - 2 = 16

= > x^2 + 1/x^2 = 16 + 2

= > x^2 + 1/x^2 = 18

Answer 1 - 18

cube on both sides of x - 1/x

= > ( x - 1 /x )^3 = 4^3

= > x^3 - 1/x^3 - 3(x*1/x)( x - 1/x ) = 4^3

= > x^3 - 1/x^3 - 3(1)(4) = 4^3

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

= > x^3 - 1/x^3 = 76

Answer 2 - 76