# Homework Help: Application of calculus

1. Jan 25, 2012

### maali5

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

A generated AC voltage has a value given by V = 4cos2θ.

You will need to use the identity cos^2⁡θ = 1/2(1+cos2θ)

2. Relevant equations

a) Find the mean value of the voltage over a full cycle (0 ≤ θ ≤ 2π) using integral calculus

b) Find the r.m.s. value of the voltage over a full cycle (0 ≤ θ ≤ 2π) using integral calculus

3. The attempt at a solution

How should I be able to solve problems like this?

Thanx

2. Jan 25, 2012

### LCKurtz

Use the formulas for mean and rms and do the integrals. Show us what you get.

3. Jan 25, 2012

### maali5

I know the two formulas but please explain to me what to do with it. I am lost.

Give me somewhere to start please.

4. Jan 25, 2012

### LCKurtz

You start with the formulas. If you know the formulas, they are nothing more than integrals. Do you know how to evaluate integrals?

I don't know how to help you until you show me what formulas you are trying and where you are stuck.