Turn on thread page Beta

C2 Trigonometry watch

Announcements
    • Thread Starter
    Offline

    13
    ReputationRep:
    Solve for x, where: -181* < x < 180*

    3cos^2x - 2sinx - 2 = 0
    Offline

    0
    ReputationRep:
    um i dont remember much but i'l try
    3cos^2x= 2sinx+2
    3(1-sin^2x)=2sinx+2
    3-3sin^2x=2sinx+2
    0= 3sin^2x + 2sinx-1
    (3sinx-1)(sinx +1)
    sinx=1/3 and sinx=-1
    and find the sin values between the limits from there
    Offline

    0
    ReputationRep:
    (Original post by ShireenHeroin)
    um i dont remember much but i'l try
    3cos^2x= 2sinx+2
    3(1-sin^2x)=2sinx+2
    3-3sin^2x=2sinx+2
    0= 3sin^2x + 2sinx-1
    (3sinx-1)(sinx +1)
    sinx=1/3 and sinx=-1
    and find the sin values between the limits from there
    the forum rules say youre not meant to do this...
    youre meant to help someone answer a question, not give them a solution.
    Offline

    0
    ReputationRep:
    Right

    Basically you need to get the 3cos^2x in terms of sin x using...

    sin^2x + cos^2x = 1

    Then what i do is then replace all the sin x's with u

    3sin^2x + 2sinx-1 = 0

    so this becomes

    3u^2 + 2u - 1 = 0

    then factorise
    Offline

    0
    ReputationRep:
    ther are forum rules
    um sorry....i thought that would help
    • PS Helper
    Offline

    14
    PS Helper
    (Original post by ShireenHeroin)
    ther are forum rules
    um sorry....i thought that would help
    Don't worry about it. Reading this could be a good idea though.
    Offline

    0
    ReputationRep:
    (Original post by ShireenHeroin)
    ther are forum rules
    um sorry....i thought that would help
    dont worry he didnt exactly ask for help just to have a question solved.

    OP - may i ask why someone is doing C2 work in the middle of the summer though?
    Offline

    15
    ReputationRep:
    (Original post by matt^)
    dont worry he didnt exactly ask for help just to have a question solved.

    OP - may i ask why someone is doing C2 work in the middle of the summer though?
    they might want to retake
    doesnt seem so farfetched does it
    Offline

    0
    ReputationRep:
    you cant retake until januay. is quite a long way off
    Offline

    12
    ReputationRep:
    (Original post by matt^)
    OP - may i ask why someone is doing C2 work in the middle of the summer though?
    I don't think doing some sort of work over the summer, how much or how little it may be, is particularly uncommon (especially for a TSR user :tongue:). People have plenty of reasons. Personally, I'm doing a little work out of interest (well, mostly out of interest - I can't honestly say that FP2 differential equations are that exciting).
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: July 22, 2009

University open days

  • University of Lincoln
    Brayford Campus Undergraduate
    Wed, 12 Dec '18
  • Bournemouth University
    Midwifery Open Day at Portsmouth Campus Undergraduate
    Wed, 12 Dec '18
  • Buckinghamshire New University
    All undergraduate Undergraduate
    Wed, 12 Dec '18
Poll
Do you like exams?
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.