Turn on thread page Beta
    • Thread Starter
    Offline

    17
    ReputationRep:
    sec^2\theta = 3tan\theta, 0\le \theta \le 360^\circ

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

    Thanks
    Offline

    0
    ReputationRep:
    sec^2=1+tan^2

    there for

    tan^2-3tan+1=0
    now you have a quadratic equation
    tan = (3+-route13)/2
    Offline

    0
    ReputationRep:
    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!
    Offline

    0
    ReputationRep:
    Wasn't this forum obliged to not give out full solutions? rather hints?
    • Thread Starter
    Offline

    17
    ReputationRep:
    (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!
    • Thread Starter
    Offline

    17
    ReputationRep:
    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!
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: August 22, 2007

University open days

  • Heriot-Watt University
    School of Textiles and Design Undergraduate
    Fri, 16 Nov '18
  • University of Roehampton
    All departments Undergraduate
    Sat, 17 Nov '18
  • Edge Hill University
    Faculty of Health and Social Care Undergraduate
    Sat, 17 Nov '18
Poll
Black Friday: Yay or Nay?
Useful resources

Make your revision easier

Maths

Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

Equations

How to use LaTex

Writing equations the easy way

Equations

Best calculators for A level Maths

Tips on which model to get

Student revising

Study habits of A* students

Top tips from students who have already aced their exams

Study Planner

Create your own Study Planner

Never miss a deadline again

Polling station sign

Thinking about a maths degree?

Chat with other maths applicants

Can you help? Study help unanswered threads

Groups associated with this forum:

View associated groups

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

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