Find h'(2), given that f(2)= -3, g(2)= 4, f'(2)= -2, and g'(2)= 7

a) h(x)= 5f(x) - 4g(x)

b) h(x)= f(x)g(x)

c) h(x)= f(x)/g(x)

d) h(x)= g(x)/1 + f(x)

I have no idea how to plug these in. If someone could please show me how to go about one, I'm sure the rest would be nearly the same.

1 answer

I'll do (c):
h(x)=f(x)/g(x)

use quotient rule in differentiation:
d(u/v)=(v*du-udv)/v²

so
h'(2)=(g(x)*f'(x)-f(x)*g'(x))/g(x)²
=(g(2)*f'(2)-f(2)*g'(2))/g(2)²
=(4*(-2)-(-3)*7)/4²
=13/16

Check my work.