Turn on thread page Beta
    • Thread Starter
    Offline

    0
    ReputationRep:
    http://img190.imageshack.us/img190/8396/img17946bt.jpg

    sinα = 2/√5
    cosα = 1/√5

    sinß = 0.6
    cosß = 0.8

    Stuck on the last part! Any suggestions?
    Offline

    15
    ReputationRep:
    Without further geometry work you should be able to write \tan \theta = \frac{sin\theta}{\sqrt{1-\sin ^{2} \theta}} as 0<\theta<\frac{pi}{2} and hence use your known values to work out tan(LMN).

    Edit: That is, i'm assuming you've done (iii) as you said 'last part'.
    Offline

    2
    ReputationRep:
    (Original post by dida87)
    http://img190.imageshack.us/img190/8396/img17946bt.jpg

    sinα = 2/√5
    cosα = 1/√5

    sinß = 0.6
    cosß = 0.8

    Stuck on the last part! Any suggestions?
    get the intersections with the x-axis [at X = -1/3 and 3/2]
    call these A and B
    call (3,0) C

    tan BNC = 3/4
    tan ANC = 5/3

    With A=BNC, B=ANB, (A+B) =ANC

    Using tan (P-Q) = (tan P - tan Q)/ (1+ tanP.tanQ)
    [(5/3)-(3/4)]/1+(5/3)(3/4)

    tan ANB = tan (ANC - BNC) = 11/27 [QED]


    Aitch

    [Sorry about the editing - too many As and Bs!]
    Offline

    0
    ReputationRep:
    (Original post by dida87)
    http://img190.imageshack.us/img190/8396/img17946bt.jpg

    sinα = 2/√5
    cosα = 1/√5

    sinß = 0.6
    cosß = 0.8

    Stuck on the last part! Any suggestions?
    Assuming you mean parts iii and iv:

    iii) sin(a + b) = sinacosb + sinbcosa

    iv) You could work out cos (a + b) using cosacosb - sinasinb, and then say that tan(a+b) = sin(a+b) ÷ cos(a+b).

    Not tried these methods out for myself, but I think they'll work. That's a pretty nice question in my opinion.
    • Thread Starter
    Offline

    0
    ReputationRep:
    Cheers people, what was cloudy is now clear!
    Offline

    6
    ReputationRep:
    (Original post by dida87)
    Cheers people, what was cloudy is now clear!
    and he who's rowdy turns to beer.....
 
 
 
Turn on thread page Beta
Updated: July 4, 2005

3,076

students online now

800,000+

Exam discussions

Find your exam discussion here

Poll
Should predicted grades be removed from the uni application process
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

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.