# Math Help - Hello Community. I could use some help on these calculus problems (Derivitiv). Thanks

1. ## Hello Community. I could use some help on these calculus problems (Derivitiv). Thanks

1.differentiate the function using the quotient rule.
fx=cos(5x)/x^4
2.fx=(x+3)/(x-2). Derivitive?
3.
Derivitive?
4.
derivitive?
5.

derivitive

6.Find the second derivative of the function.

f(x) = 2x + 25x−2

7.Find f '''(x).

2. it seems as though you're stuck with the quotient rule, how about you try one and I'll see where you're having problems and try to help you

3. ok thank you. I have tried all of them and got wrong answers. I will try number 2.
fx= (x+3)/(x+2)
=x+2-x-3/x^2+4x+4
=-1/x^2+4x+4??

4. Originally Posted by giants1080
ok thank you. I have tried all of them and got wrong answers. I will try number 2.
fx= (x+3)/(x+2)
=x+2-x-3/x^2+4x+4
=-1/x^2+4x+4??

So i think you want the deriv of f(x)

$f(x)=\frac{x+3}{x+2}$

$f'(x)=\frac{(x+2)\cdot 1-(x+3)\cdot 1}{(x+2)^2}$

and simplify from there

Notice that the first '1' is the deriv of the numerator and the second '1' is the deriv of the denominator