Derivative of a Polynomial Function?

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Homework Statement



Find derivative of function?
if f(x) = (x^2 + 3x -2 ) (x^3-4)
Find f`(x)

Homework Equations



FOIL or Multiply both

The Attempt at a Solution



I get
5x^4 + 12x^3 - 6x^2 -8x-12

is this right?
 
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Yes, it's correct. Why do you think it might not be??
 
just checking
 
I'd use the product rule.
 
10min said:

Homework Statement



Find derivative of function?
if f(x) = (x^2 + 3x -2 ) (x^3-4)
Find f`(x)

Homework Equations



FOIL or Multiply both

The Attempt at a Solution



I get
5x^4 + 12x^3 - 6x^2 -8x-12

is this right?

yes i believe it is.
 
You could check by using the product rule as ducnguyen2000 suggested:
the derivative of f(x) = (x^2 + 3x -2 ) (x^3-4) is (x^2+ 3x- 2)'(x^3- 4)+ (x^2+ 3x- 2)(x^3- 4)'.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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