Question

How do you differentiate `H(x)=(x+x^-1)^3`?

Answer 1

`H'(x)=3(x^2+1-x^(-2)-x^(-4))`

Explanation:

`H'(x)=3(x+x^(-1))^2*(1-x^(-2))`
`H'(x)=3(x^2+2+x^(-2))*(1-x^(-2))`
`H'(x)=3(x^2+2+x^(-2)-1-2x^(-2)-x^(-4))`