Understanding Differential Calculus: Solving Homework Equations

s883
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Homework Statement


Could anyone explain me how to solve this?

Homework Equations



f(x) =
1/x2 + 4x + 9 + x4 , f’”’(-2) =


The Attempt at a Solution

 
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Hello s883! :smile: It means to take the 4th derivative of the given function f(x) and then evaluate the resulting expression at x = -2. And I would probably put calculus questions in the calculus forum for next time :wink:
 
I assume you mean f(x) = 1/x^2 + 4x + 9 + x^4= x^{-2}+ 4x+ 9+ x^4.

Can you find f'(x) using the "power rule" ((x^n)'= n x^{n-1})?

What about f'' and f'''?

Now do f''''.
 
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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