multiplying and dividing derivatives

K

kristoball

New member
Joined
Mar 27, 2012
Messages
11
hello, i just need some help with finding the derivative of an equation with division/multiplication in it given a value of a function at a point, the value of a derivative at the same point and the equation of a seperate function. Below are examples of mulitplication and division of the types I need help with. If anyone could show me a step by step explaination, or what i need to do to start, i would greatly appreciate it. thanks!

Multiplication:
1. If f and g are differentiable functions and f(-1)=5, f`(-1)=10, g(-1)=4 and g`(-1)=3 then what is the value of (fg)`(-1?)
2. Suppose f(5)=1 and f`(5)=6. if g(x)=x2f(x) then find g`(5)

Division:
1. Suppose that g(5)=9 and g`(5)=5. Find the slope of the tangent line to y=(x2+2)/g(x) at (5, 3)

Thanks!
 
kristoball said:
hello, i just need some help with finding the derivative of an equation with division/multiplication in it given a value of a function at a point, the value of a derivative at the same point and the equation of a seperate function. Below are examples of mulitplication and division of the types I need help with. If anyone could show me a step by step explaination, or what i need to do to start, i would greatly appreciate it. thanks!

Multiplication:
1. If f and g are differentiable functions and f(-1)=5, f`(-1)=10, g(-1)=4 and g`(-1)=3 then what is the value of (fg)`(-1?)

(f*g)' = (f)*(g') + (f')*(g)

2. Suppose f(5)=1 and f`(5)=6. if g(x)=x2f(x) then find g`(5)

Use the hint above

Division:

1. Suppose that g(5)=9 and g`(5)=5. Find the slope of the tangent line to y=(x2+2)/g(x) at (5, 3)

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


Thanks!
Click to expand...

.
 
"f" is NOT an "equation", it is a function. And this is your exercise- you told us what f and f' are, at least the important values.
 
You must log in or register to reply here.
Top