You are Here: Home >< Maths

C3 Trig Identities

Announcements Posted on
Would YOU be put off a uni with a high crime rate? First 50 to have their say get a £5 Amazon voucher! 27-10-2016
1. http://store.aqa.org.uk/qual/gce/pdf...W-QP-JAN11.PDF
http://store.aqa.org.uk/qual/gce/pdf...W-MS-JAN11.PDF

7B) Unsure on the last stage of this question as I'm left with:

-2cosec^2x/-cot^2x=50

to get to Sec^2x=25

thanks
2. cosec^2x = 1 + cot^2x

so you have -2(1+cot^2x)/-cot^2x=50

You can get rid of the negatives as they are on both the top and bottom

2((sin^2x+cos^2x)/sin^2x)/cot^2x=50

2(1/sin^2x)/cos^2x/sin^2x=50
The sin^2x cancel out to give you:
2 x1/cos^2x=50
therefore... 2sec^2x=50
sec^2x=25

Hope that makes sense

EDIT: You could also go from
2cosec^2x/cot^2x to 2(1/sin^2x)/cos^2x/sin^2x

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: May 25, 2012
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

Find out here

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

Chat with other maths applicants