You are Here: Home >< Maths

# Core 4 trig question watch

1. Show that cos2x/cosx+ sixx = cosx-sinx. I know trig identities need to be used, but i do not know how to get the answer at all.
2. (Original post by stefl14)
Show that cos2x/cosx+ sixx = cosx-sinx. I know trig identities need to be used, but i do not know how to get the answer at all.
Focus on the left hand side first.

Try replacing the Cos2x with some trig identities.
3. well yes i get (cosx)^2-(sinx)^2/cos x + sin x but not quite sure why this is cos x - sin x
4. (Original post by stefl14)
well yes i get (cosx)^2-(sinx)^2/cos x + sin x but not quite sure why this is cos x - sin x
Factorise the numerator -- it's the difference of two squares.
5. anyone?
6. oke thanks, I need to recognise this stuff more easily...

### 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 2, 2011
Today on TSR

### Edexcel GCSE Maths Unofficial Markscheme

Find out how you've done here

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