You are Here: Home >< Maths

# cartesian equation- trig c4 ocr mei help?

Announcements Posted on
Last day to win £100 of Amazon vouchers - don't miss out! Take our quick survey to enter 24-10-2016
1. http://mei.org.uk/files/papers/c410ju_weio.pdf

q3 - i dont understand how to do it
i got to half sin 2 theta but no idea from there
2. (Original post by liverpool2044)
http://mei.org.uk/files/papers/c410ju_weio.pdf

q3 - i dont understand how to do it
i got to half sin 2 theta but no idea from there
All you have to do here is just show that, given the parameterisation, show that . So you know that and . Sub those into and you should get easily from .
3. (Original post by IrrationalRoot)
All you have to do here is just show that, given the parameterisation, show that . So you know that and . Sub those into and you should get easily from .
when i do this i get 2sin^2 2theta?
4. (Original post by liverpool2044)
when i do this i get 2sin^2 2theta?
Which part do you get for? Is that what you got for ? If that's the case, then remember that .
So and you should be able to finish it from there.
5. (Original post by IrrationalRoot)
Which part do you get for? Is that what you got for ? If that's the case, then remember that .
So and you should be able to finish it from there.
4(0.5sin2theta)^2? im not getting the value
6. (Original post by liverpool2044)
4(0.5sin2theta)^2? im not getting the value
y = sin(theta)cos(theta)
therefore, 2y = 2sin(theta)cos(theta)
therefore, 2y = sin(2theta)
you have x = cos(2theta) and y = sin(2theta)
cos(2theta)^2 + sin(2theta)^2 = 1
I imagine you can do the rest (just subbing in y and x appropriately)
7. (Original post by liverpool2044)
4(0.5sin2theta)^2? im not getting the value
, as required.

The last part follows from the identity .
8. ahh makes sense now thanks guys

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: April 16, 2016
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:
Today on TSR

### How does exam reform affect you?

From GCSE to A level, it's all changing

Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read here first

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams