How do you differentiate & integrate e to the x?

pillar
Messages
35
Reaction score
0
1.a Evaluate the following. Show all work.
http://img90.imageshack.us/img90/289/problemu.png
1.b Differentiate.
http://img293.imageshack.us/img293/1440/problem2.png

Homework Equations


ƒ b-a f(x)-g(x)


The Attempt at a Solution



1.a.http://img511.imageshack.us/img511/1205/problemews.png

1.b.http://img512.imageshack.us/img512/4250/problem2ans.png
 
Last edited by a moderator:
Physics news on Phys.org
e^2x does not integrate to 2e^2x because differentiation of 2e^2x is 4e^2x which is not equal to the e^2x.
 
Presumably, you know that (e^x)'= e^x and \int e^x dx= e^x+ C.

To differentiate e^{2x}, use the chain rule, df/dx= (df/du)(du/dx), with u= 2x. Then f(u)= e^u so df/du= e^u and u= 2x so du/dx= 2.

To integrate e^{2x}, use the "inverse" of the chain rule- substitution. Let u= 2x so du= 2dx or dx= (1/2)du.

The one multiplies by 2, the other divides by 2.
 
HallsofIvy said:
Presumably, you know that (e^x)'= e^x and \int e^x dx= e^x+ C.

To differentiate e^{2x}, use the chain rule, df/dx= (df/du)(du/dx), with u= 2x. Then f(u)= e^u so df/du= e^u and u= 2x so du/dx= 2.

To integrate e^{2x}, use the "inverse" of the chain rule- substitution. Let u= 2x so du= 2dx or dx= (1/2)du.

The one multiplies by 2, the other divides by 2.

So e^2x differentiated would become 2e^2x?
 
pillar said:
So e^2x differentiated would become 2e^2x?

(I assume you mean e2x differentiated would become 2e2x?)

Yes, that's right. :smile:

(To see why, apply the chain rule with f(x) = ex and g(x) = 2x.)
 
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