Question

Homework Help - Thanks!
Differentiate:
a) g(x)=2e^(-x/2)
b) h(x)=In(x^2+3x)

Answer 1

b looks like simple chain rule

a looks like u substitution

Answer 2

Thank you!

Answer 3

would you like to actually work through them?

Answer 4

Yes please

Answer 5

We'll start with b. recall that the derivative of ln(x) = 1/x

As such, the derivative of In(x^2+3x) = 1/(x^2+3x)

but that's not enough. the chain rule applies here so we multiply by the derivative of (x^2+3x)

Answer 6

I am writing this down, its been 20 years since I have been in school so I am slowly learning again. I just need to get through this last math class. thanks so much...

Answer 7

Ah, well this should be a decent enough place for actually learning the math. What you want to do is get the elementary derivatives/formulas memorized. Keep them up in a tab while you work through problems.

2e^(-x/2)
things to note:
* the 2 is a constant multiplier. the derivative of 2g(x) = 2g'(x) [it just means we can ignore it and leave it out while we take the derivative of the rest]
* we know the derivative of e^x but not e^(-x/2)

Answer 8

Good advice.

Answer 9

2e^(-x/2)
if we make u = -x/2
du = -1dx

so we have to differentiate
2e^(u).
the derivative of e^x is e^x.

2e^u * du because we have to multiply by the derivative of u.

Answer 10

ok...you have been most helpful!

Answer 11

http://www.wolframalpha.com/input/?i=derive+2e%5E%28-x%2F2%29++

anyhow I have to go to school. check this out and feel free to message me if you have things you need help with

Answer 12

Will do thanks!