Differentiate e^x and Trig Functions

gabyoh23
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Homework Statement


Differentiate
e^x * cotx / 5sqrtx^2
[Sorry for not using the formatting things. They didn't seem to be working for me, and this is urgent!]


Homework Equations


The quotient rule seems like that's the way to go...


The Attempt at a Solution


At first I tried using the product rule on the numerator, then plugging that into the quotient rule formula, but that was needlessly complicated. So, I went straight into using the quotient rule, but I got a huge messy equation. Could anyone clarify what I SHOULD be getting?

All help is greatly appreciated!
 
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Both ways are correct. Either do product rule inside of Quotient or do Product then do Quotient. Both will be potentially messy.
 
also is that 5sqrt(x^2) or (5sqrt(x))^2 or what?
because that should simple things out for you.
 
It's 5sqrt(x^2).
Sorry about that.
 
The quotient rule is never worth remembering IMO. Just use the product rule and think of the derivative of a quotient as

<br /> \frac{d}{dx}\left( \frac{f(x)}{g(x)} \right) = \frac{d}{dx}\left(f(x) \ g(x)^{-1}\right)<br />

and don't forget to apply the chain rule when differentiating g(x)^{-1}.

It's too easy to forget the quotient rule on an exam, and also too easy to screw it up when you're in a rush to get everything done in 50 minutes on a midterm. The product rule and chain rule are easy though, and critical to know anyways.
 
What's the square root of x^2?

that will make it a little simpler.
 
Last edited:
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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