Hey! Sign in to get help with your study questionsNew here? Join for free to post

Heinemann Core 3 Book: Trig Q

Announcements Posted on
Would YOU be put off a uni with a high crime rate? First 50 to have their say get a £5 Amazon voucher! 27-10-2016
    • Thread Starter

    OK PEOPLE dumb nacero2000 here again...bestow me with ur knowledge

    given that 5sin x cos y + 4cos x sin y = 0 and cot x = 2 wot is the value of cot y??

    put one term on one side of the equals sign and keep the other term on the other side.
    Then divide one side by the other and see what you've got.

    It follows from cot(x) = 2 that cos(x) = 2sin(x). So

    5sin(x)cos(y) + 8sin(x)sin(y) = 0
    sin(x)(5cos(y) + 8sin(y)) = 0
    5cos(y) + 8sin(y) = 0 . . . . . because sin(x) is not zero
    5cos(y) = -8sin(y) . . . . . if sin(y) were zero then cos(y) would be too; so sin(y) is not zero
    cos(y)/sin(y) = -8/5
    cot(y) = -8/5
Updated: April 7, 2005
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.

Would you rather be able to
Useful resources

Make your revision easier


Maths Forum posting guidelines

Not sure where to post? Read here first


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
Study resources

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

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