Find the derivative of (b/(a+z^2))^2

Question

Assuming that a and b are constants...

Answer 1

f= b(a+z^2)^-2

f'= -2(a+z^2)^-3 * 2z

=-4z/(a+z^2)^3

check that carefully.

Answer 2

How did you get the -2 at the beginning?

Answer 3

f=u^b
f'= b*u^(b-1)

in this case, b=-2

Answer 4

But why is b -2?

Answer 5

Check up the power rule in your notes.
d(x^n)/dx = nx^(n-1)
The power is -2 in the given question.

Remember: "check that carefully."