You are Here: Home >< Maths

# C3 Trig watch

1. Can someone please show me the step by step mehtod to work this out please, i don't know how to do these.

Thanks
2. sec^2=1+tan^2

there for

tan^2-3tan+1=0
now you have a quadratic equation
tan = (3+-route13)/2
3. For this you need to use one of the more obscure trig identities to get it all in one trigonometric ratio. Spot the quadratic equation and solve it. Remember there are 4 answers!

Edit: Edited in the interest of not handing out a full solution. Sorry TPTB!
4. Wasn't this forum obliged to not give out full solutions? rather hints?
5. (Original post by mathsman)
sec^2=1+tan^2

there for

tan^2-3tan+1=0
now you have a quadratic equation
tan = (3+-route13)/2
Ahh cheers for this, so i need identities to worh this out. And the last line i assume is the quadratic formula your using. I will give it a shot and post the answers, cheers!
6. Ok i get 3 +- rt5/ 2, that gives me 2 of the solutions of theta, 69.1 and 20.1, and the others i presume i work out using the graph? ...thanks alot 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: August 22, 2007
Today on TSR

### Cambridge interviews

Find out who is getting invitations

### University open days

• Heriot-Watt University
School of Textiles and Design Undergraduate
Fri, 16 Nov '18
• University of Roehampton
Sat, 17 Nov '18
• Edge Hill University
Faculty of Health and Social Care Undergraduate
Sat, 17 Nov '18
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