Taking imaginary integral and derivative

1. Nov 17, 2012

chaotic

1. The problem statement, all variables and given/known data

when im solving quantum problem, i see an equation like e^(-kx) e^(icx) i is imaginary. how can i take the integral and derivative of this function

2. Relevant equations

e^ix ) cosx + isinx

3. The attempt at a solution

actually i tried e^x(-k+ic) and i said the derivative is just (-k+ic)* e^x(-k+ic) :)

2. Nov 17, 2012

voko

What you did is correct. You can treat complex constants as if they were real in differentiation and integration. However, I would recommend getting some introductory text on complex analysis and study it at least until differentiation and integration are introduced.

3. Nov 17, 2012

chaotic

4. Nov 17, 2012

voko

That's because it is confused by the input. Note it treats "icx" as all caps CIX and assumes it is a constant.

5. Nov 17, 2012

chaotic

agh :) thank you very much i understand now :)

6. Nov 17, 2012

haruspex

Wolfram seems to have treated the second x as some constant X. In fact, it looks suspiciously as though it has interpreted "icx" as Roman Numerals "CIX" (109). Bizarre.

7. Nov 17, 2012

chaotic

yes it is very confusing im trying to find solution for 2 hours just because of that it is funny it takes my precious time :)

8. Nov 17, 2012

voko

A space after i and before c does wonders. But the output is still a bit odd.

9. Nov 17, 2012

SammyS

Staff Emeritus
Yes, $\ \ i(c+i k) e^{-k x+i c x}\ \$ is a bit odd, isn't it?