# Homework Help: Integration using exponentials

1. Oct 17, 2012

### g.lemaitre

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

the integral table says when you have the above form this will be the answer:

2. Relevant equations

3. The attempt at a solution

I looked at the integral table here

http://integral-table.com/integral-table.html#SECTION00006000000000000000

and it says erf - I don't know what that means. In any case the erf x√a does not appear in the answer. I also don't understand the step

A√(λ/π) = A = √λ/π

I also don't see why there is no two in the denominator.

2. Oct 17, 2012

### Ray Vickson

The definition of erf(x) IS include in the table.

RGV

3. Oct 17, 2012

### g.lemaitre

Why is there no 2 in the denominator. I still don't know what erf means. I also don't understand the step

A√(λ/π) = A = √λ/π

4. Oct 17, 2012

### clamtrox

5. Oct 17, 2012

### clamtrox

Because the integral is from -∞ to ∞, not from 0 to ∞.

It means "error function". Don't worry about that.

You are not reading it correctly, that's why. What it reads is
A√(π/λ) = 1
therefore
A = √λ/π

6. Oct 17, 2012

### g.lemaitre

ok, thanks for the help.