x Turn on thread page Beta
 You are Here: Home >< Maths

# C3 MEI help! watch

1. http://www.mei.org.uk/files/papers/c305ju_dskjtr.pdf

I can seem to do q8i.

xsin3x = 0

so sin3x = 0
So I take the arcsin of both sides

and end up with 3x = 0?

But the mark scheme says that sin3x = pi?

HELP!
2. You can't just take the arcsin. You have to consider all of the possible solutions. Draw a graph of , look at all the places where it cuts the x-axis, and you'll see what I mean.
3. sin3x = 0 & x = 0.
sinpi = 0
3x must then equal pi.
x = pi/3.
4. when does sin x = 0? just when x =0? - Draw a Sine graph to find out if you are unsure I did this question about an hour ago haha
5. yeah I came across this problem. If you draw a sign graph you'll see that sin(pi) is 0
so you can go from there..

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:
Updated: January 19, 2010
Today on TSR

### How do I turn down a guy in a club?

What should I do?

Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams