# Differential of a complex number

1. Oct 28, 2012

### VaccumEnergy

What is d/di(x+iy)?

2. Oct 28, 2012

### DonAntonio

I'm guessing you meant

$$\frac{d}{di}(x+iy)=y$$

Assuming all the usual stuff in real and complex analysis apply here, of course.

DonAntonio

3. Oct 28, 2012

### Klungo

Isn't the imaginary unit a constant?

4. Oct 28, 2012

### DonAntonio

I guess it is, yet the OP regards it as a variable in his question, so...

DonAntonio