You are Here: Home >< Maths

# Trig functions and equation watch

1. i need help with the question in this link...
im not sure how to work it out..

https://imgur.com/a/rIB0A
2. (Original post by Chez 01)
i need help with the question in this link...
im not sure how to work it out..

https://imgur.com/a/rIB0A
(a) All you need to do is firstly express the equation entirely in terms of , then just use the given substitution to obtain what they have.

(b) (i) That's just a quadratic to solve, I'm sure you can do this.

(ii) Use the fact that we denoted , and along with the solutions to (i) to then solve for in the given domain.
3. (Original post by Chez 01)
i need help with the question in this link...
im not sure how to work it out..

https://imgur.com/a/rIB0A

and when you expand that you get

You just wrote in your working.
4. (Original post by RDKGames)
(a) All you need to do is firstly express the equation entirely in terms of , then just use the given substitution to obtain what they have.

(b) (i) That's just a quadratic to solve, I'm sure you can do this.

(ii) Use the fact that we denoted , and along with the solutions to (i) to then solve for in the given domain.
thankyou for replying....so i got 90 and 19.5 and 160.5 degrees for the last question...is that right?
5. (Original post by Notnek)

and when you expand that you get

You just wrote in your working.
oh okay...thankyou

### 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: March 10, 2018
Today on TSR

### Edexcel C3 Maths Unofficial Markscheme

Find out how you've done here

### 1,133

students online now

Exam discussions

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