Question

If f(3)=−3, g(3)=9, f′(3)=1, and g′(3)=2,

Find (f/(f−g))′(3).

Answer 1

(f/(f-g))' = [f'(f-g) - f(f'-g')]/(f-g)^2

= [(1)(-3-9) - (-3)(1-2)]/(-3-9)^2
= -5/48