# How do I differentiate

1. Mar 28, 2008

### j-lee00

How do I differentiate

f(x,t) = expi(kx-wt)

f'(x,t) = ?
f''(x,t) = ?

2. Mar 28, 2008

### cristo

Staff Emeritus
What do your primes denote differentiation with respect to?

Write your expression as exp(ikx).exp(-iwt). Depending upon what you are differentiating with respect to, one of these terms can be treated as a constant. You know how to differentiate exp(x), right?

3. Mar 28, 2008

### j-lee00

Does it make a difference if "i" is involved?

4. Mar 28, 2008

No .