You are Here: Home

# Heinemann Core 3 Book: Trig Q

Announcements Posted on
International student planning UK study in 2016? Take our short survey and we’ll send you a £5 Amazon voucher 03-05-2016
Talking about ISA/EMPA specifics is against our guidelines - read more here 28-04-2016
1. 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??
2. 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.
3. 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.

This forum is supported by:
Today on TSR

How did it go?

Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read here first

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams