F''(x) Second Derivative problem

oowhitey
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Homework Statement


find f''(x) <-- second derivative
f(x) = 3e^-x2 <-- that 2 is x squared

Homework Equations





The Attempt at a Solution


my attempt was 6x^2 e^x2
 
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Try taking the first derivative first, then take the second derivative.
 
oowhitey said:

Homework Statement


find f''(x) <-- second derivative
f(x) = 3e^-x2 <-- that 2 is x squared

The Attempt at a Solution


my attempt was 6x^2 e^x2


On the right track, but you're not quite remember your rules correctly.

For the first derivative, use the chain rule. Derivative of the outside 3e^(x^2) times the derivative of the inside (x^2)

Once you've got that, you're going to have a function that is an x times an exponential along the lines of ?xe^(x^2). From there, you need to use the product rule. Which is the derivative of the first function (?x) times the second function (e^(x^2)) plus the first function times the derivative of the second function. Or f'(x)g(x)+f(x)g'(x) (should be familiar from your text) On the derivative of your second function, don't forget the chain rule again!

Hopefully that helps, or if not, that someone can come and correct me.
 
thanks that helped a bunch i think i got it.
 
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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