How Do You Apply the Chain Rule to Differentiate y=e^(√x)?

physics604
Messages
92
Reaction score
2
1. Find the derivative of y=e\sqrt{x}

Homework Equations



Chain rule

The Attempt at a Solution



y=eu

\frac{dy}{du}= ueu-1


u=\sqrt{x}

\frac{du}{dx}= \frac{1}{2}x-1/2

\frac{dy}{dx}= \sqrt{x}e\sqrt{x}-1 × \frac{1}{2}x-1/2

= \sqrt{x} \frac{e^\sqrt{x}}{e} × \frac{1}{2\sqrt{x}}

= \frac{e^\sqrt{x}}{2e}

The answer to this question is \frac{e^\sqrt{x}}{2\sqrt{x}}. What did I do wrong?

Any help is much appreciated.
 
Last edited:
Physics news on Phys.org
Nevermind, I got it.

The derivative of e^x is still e^x.
 
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...
Back
Top