Derivatives of e^x: Solutions and Explanations

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In summary, our teacher accidentally jumped ahead in the course and I was able to understand the questions because of the grounding we had today.
  • #1
Elihu5991
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Homework Statement


Find the derivative of these e^x functions [paraphrased]


Homework Equations


[itex]x^{2} e^{x}[/itex]


The Attempt at a Solution


[itex]2x e^{x}[/itex]

This is how I believe it to be correct from my understanding. It does feel wrong, with the answers agreeing with the feeling.
 
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  • #2
Elihu5991 said:

Homework Statement


Find the derivative of these e^x functions [paraphrased]


Homework Equations


[itex]x^{2} e^{x}[/itex]


The Attempt at a Solution


[itex]2x e^{x}[/itex]

This is how I believe it to be correct from my understanding. It does feel wrong, with the answers agreeing with the feeling.

You need to use the product rule to differentiate that.

$$\frac{d}{dx}(u\cdot v)=u(\frac{dv}{dx})+ v(\frac{du}{dx})$$
 
  • #3
the function [itex]x^2e^x[/itex] is a product of two functions. So what rule do you need to use, to take the derivative?
 
  • #4
Can't believe I didn't notice the use of the product rule. As I was progressing through the question, I wasn't sure of one new thing: is two [itex]e^{x}[/itex] equal to [itex]e^{x}[/itex] or [itex]2e^{x}[/itex]? I reckon it's the latter, but the answers are in the simplest form and doesn't seem to fit; unless I've made another minute error.
 
  • #5
##e^x + e^x = 2e^x## if that is what you're asking. Pretty standard stuff...
 
  • #6
Elihu5991 said:
Can't believe I didn't notice the use of the product rule. As I was progressing through the question, I wasn't sure of one new thing: is two [itex]e^{x}[/itex] equal to [itex]e^{x}[/itex] or [itex]2e^{x}[/itex]? I reckon it's the latter, but the answers are in the simplest form and doesn't seem to fit; unless I've made another minute error.

Well try to look at x^2e^x as u=x^2 and v=e^x

so (uv)'=u'v+v'u. Now just compute that and you will find your derivative.

You should get 2xe^x+x^2e^x=x(2e^x+xe^x)=xe^x(x+2)
 
  • #7
Yeah that's what I thought. But I had to check as I was getting problems. It would be my working-out. We were doing some different than standard stuff with Euler's Number today, so I wondered if it applied to this situation as well.
 
  • #8
mtayab1994 said:
Well try to look at x^2e^x as u=x^2 and v=e^x

so (uv)'=u'v+v'u. Now just compute that and you will find your derivative.

You should get 2xe^x+x^2e^x=x(2e^x+xe^x)=xe^x(x+2)

Did you differently simplify it? The answer in my book: [itex]xe^{x}(2+x)[/itex]
 
  • #9
Elihu5991 said:
Did you differently simplify it? The answer in my book: [itex]xe^{x}(2+x)[/itex]

No it's the same look at my post.
 
  • #10
Oh whoops, I somehow didn't see that segment ...
 
  • #11
Thankyou everyone for your help.

P.S How do I mark this topic as [SOLVED] ?
 
  • #12
Elihu5991 said:
Thankyou everyone for your help.

P.S How do I mark this topic as [SOLVED] ?

There's no solved prefixes on the forums.
 
  • #13
Oh ok. Well, thank you!

P.S Turns out that our teacher accidentally jumped ahead in the course. Explaining why I seemed to ask silly questions, that I'm now able to since we had the grounding today.
 

Related to Derivatives of e^x: Solutions and Explanations

1. What is the derivative of e^x?

The derivative of e^x is simply e^x. This means that the derivative of a function with e^x as its base will always be e^x, regardless of the power or exponent.

2. How do you find the derivative of a function with e^x as its base?

To find the derivative of a function with e^x as its base, you simply use the chain rule. This means that you multiply the function by the derivative of the exponent, which is always 1, and then multiply by the derivative of the entire function, which is e^x.

3. Can you give an example of finding the derivative of e^x?

Sure! Let's say we have the function f(x) = 2e^x. Using the chain rule, the derivative would be f'(x) = 2 * 1 * e^x = 2e^x. As you can see, the derivative is simply e^x, just like we discussed in the first question.

4. Why is e^x such an important function in calculus?

E^x is important in calculus because it is its own derivative, meaning that its derivative is itself. This makes it a useful tool for solving more complex functions, as well as for applications in physics and engineering.

5. Are there any other important properties or rules for derivatives of e^x?

Yes, there are a few other important properties and rules for derivatives of e^x. For example, the derivative of a constant times e^x is simply that constant times e^x. Additionally, the derivative of ln(e^x) is simply 1. These properties can be helpful when solving more complex functions involving e^x.

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