# Math Help - Need help with this differentiation question

1. ## Need help with this differentiation question

Can anyone help me figure this out?

If f(7)=6 , f ' (7)=9 , g(7)=10 , and g ' (7)=7 then:

(f+g) ' (7) =

(fg) ' (7) =

thanks

2. Hello,
Originally Posted by coldfire
Can anyone help me figure this out?

If f(7)=6 , f ' (7)=9 , g(7)=10 , and g ' (7)=7 then:

(f+g) ' (7) =

(fg) ' (7) =

thanks
Using basic rule of differentiation, $(f+g)'(x)=f'(x)+g'(x)$

Using multiplication rule : $(fg)'(x)=f'(x)g(x)+f(x)g'(x)$

.... !

3. ahhh, so simple.. I forgot (fg)' = f'(x)g(x) + g'(x)f(x)

thanks