Question

find 3rd derivate (x^2) + sqrt x^5 - (1/x^2)

Answer 1

I would first rewrite your problem:
(x^2)+(x^5/2)-(x^(-2))
So then the first derivative would be:
2x+(5/2)x^((5/2)-1)+2x^(-2-1)= 2x+(5/2)x^(3/2)+2x^(-3)
Second derivative:
2+15/4x^(1/2)-6x^(-4)
I'll leave it to you to find the third derivative.