You are Here: Home >< Maths

# Reduction Formula Help watch

1. Hi, I'm having trouble with my Reduction Formula homework.

Consider In = (Integral between pi/2 and 0 of) sin2n(theta)/sin (theta) , where n is a non negative integer.

Using sinA - sinB = 2cos[(A+B)/2]sin[(A-B)/2], derive the reduction formula

In - I(n-1) = [2(-1)^(n-1)] / (2n -1)

I realise it may be hard to understand as I can't use latex but any help would be much appreciated!
2. I think the hint is in the . If you write this out then you get , and then you can apply your identity to what's in the brackets. You'll notice that nice things cancel and you get something you can integrate.
3. Thanks for the help

I had a feeling it was something simple. But then I wondered whether using what they had given was sort of cheating and I had to derive that some other way.
4. (Original post by mknox669)
I had a feeling it was something simple. But then I wondered whether using what they had given was sort of cheating and I had to derive that some other way.
Usually when a hint is given it's because it's the best way to go about it and other ways of tackling it will make you hit brick walls -- use all the hints you're given It's definitely not cheating.

### Related university courses

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: April 3, 2011
The home of Results and Clearing

### 2,594

people online now

### 1,567,000

students helped last year
Today on TSR

### University open days

1. Keele University
Sun, 19 Aug '18
2. University of Melbourne
Sun, 19 Aug '18
3. Sheffield Hallam University
Tue, 21 Aug '18
Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams