You are Here: Home >< Maths

# cartesian equation- trig c4 ocr mei help? Watch

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

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 16, 2016
Today on TSR

...in schools

### I think I'm transgender AMA

Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• 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

## Groups associated with this forum:

View associated groups
Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.