Find a formula for the derivatives of the function m(x)=1/(x+1)

Question

Please help.....Any assistance would be greatly appreciated.

Answer 1

Why plural? There is only one derivative of that function.

Let x+1 = u, so that
m(x) = m{u(x)}, m(u) = 1/u, and
du/dx = 1

Then use the chain rule
dm/dx = dm/du*du/dx
= -1/u^2 = -1/(x+1)^2