Question

Given that:

f(−4)=4, f′(−4)=3,
g(−4)=8, g′(−4)=9,

calculate the following:

(fg)′(−4)=


(f/g)′(−4)=


(g/f)′(−4)=

Answer 1

@mathmale

Answer 2

By product rule we have,\[\large\rm (fg)'=f'g+fg'\]Evaluated at x=-4 gives us,\[\large\rm (fg)'(-4)=f'(-4)g(-4)+f(-4)g'(-4)\]Ya? :)
Any confusion there?

Answer 3

a little

Answer 4

oh wait

Answer 5

(3*8)+(4*9)

Answer 6

is that right?

Answer 7

Good good good.

Answer 8

For the others,
remember your quotient rule?

Answer 9

a little bit

Answer 10

Medals 1
((3*8)-(4*9))/(8^2)

Answer 11

?

Answer 12

\[\large\rm \left(\frac{f}{g}\right)'=\frac{f'g-fg'}{g^2}\]
Mmm yes looks good!

Answer 13

how would you do the last one thought, im a little confused?

Answer 14

Umm you just follow your rule for quotient.\[\large\rm \left(\frac{g}{f}\right)'=\frac{g'f-gf'}{f^2}\]Dtop*bottom minus Dbottom*top all divided by bottom^2