Turn on thread page Beta

Help with curves and identities and whatnot watch

    • Thread Starter
    Offline

    15
    ReputationRep:
    To be perfectly honest I have no idea what topic this comes under, but anyway here goes:

    Show that the curves y = 3sin\theta + 1 and y=2cos2\theta will intersect when

    2sin2 + 3sin\theta- 1 = 0

    I've spent 20 mins trying to work it out but I have no clue what to do. I haven't seen a question like this before...
    Offline

    16
    ReputationRep:
    When do two curves intersect? When they both go through the exact same point.

    How do you work out the 1 point that two curves go through?
    • Thread Starter
    Offline

    15
    ReputationRep:
    (Original post by claret_n_blue)
    When do two curves intersect? When they both go through the exact same point.

    How do you work out the 1 point that two curves go through?
    uhh....simultaneous equation?
    Offline

    16
    ReputationRep:
    (Original post by Alleykat606)
    uhh....simultaneous equation?
    Yeap
    Offline

    16
    ReputationRep:
    (Original post by Alleykat606)
    uhh....simultaneous equation?
    set them equal to each other

    spot that the answer has no cos

    Use a well know identity to change your cos to sin
    • Thread Starter
    Offline

    15
    ReputationRep:
    (Original post by claret_n_blue)
    Yeap
    but what does the last equation have to do with it? :confused:
    Offline

    16
    ReputationRep:
    (Original post by Alleykat606)
    but what does the last equation have to do with it? :confused:
    That's the answer to the question. You are showing the curves intersect at that point. So after your calculations are complete, you should get that answer.
    • Thread Starter
    Offline

    15
    ReputationRep:
    (Original post by claret_n_blue)
    That's the answer to the question. You are showing the curves intersect at that point. So after your calculations are complete, you should get that answer.
    OHHH I get it now. Wording just confused me for a second there. Thanks ever so much!
    Offline

    16
    ReputationRep:
    (Original post by Alleykat606)
    OHHH I get it now. Wording just confused me for a second there. Thanks ever so much!
    No worries
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: January 5, 2013

University open days

  • Manchester Metropolitan University
    Postgraduate Open Day Postgraduate
    Wed, 14 Nov '18
  • University of Chester
    Chester campuses Undergraduate
    Wed, 14 Nov '18
  • Anglia Ruskin University
    Ambitious, driven, developing your career & employability? Aspiring in your field, up-skilling after a career break? Then our Postgrad Open Evening is for you. Postgraduate
    Wed, 14 Nov '18
Poll
Have you ever experienced bullying?
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.