Derivatives product rule help

1. Nov 11, 2009

JimmyA

1. The problem statement, all variables and given/known data
find the dy/dx of y= 4- x (to the 2nd power) sin x

2. Relevant equations
is there a rule?

3. The attempt at a solution
nothing

2. Nov 11, 2009

Bensky

Re: derivatives

Is it 4 - (x^2*sin(x)) or ((4-x)^2 * sin(x))?

You will need the product rule for the first case, or for the second case a combination of the product rule and the chain rule.

Product rule: f'(x) * g(x) + g'(x) * f(x)
Chain rule: f'(g(x)) * g'(x)

3. Nov 11, 2009

Bensky

Re: derivatives

Ok, per the visitor message I got from you..you don't understand how to use the product rule.

Use the following information:
Let f(x) = x^2 and g(x) = sin(x). The derivative of sin(x) is cos(x) - memorize this. Use the power rule for the derivative of x^2.

f'(x) refers to the derivative of f(x), and g'(x) refers to the derivative of g(x). You should now be able to use the product rule to calculate the derivative.

If you need more help someone else will have to help you, I have to leave now.

4. Nov 11, 2009

JimmyA

Re: derivatives

thank you very much

Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook