- the co-ordinates of any point, P, on the unit circle are where is the angle through which OP has rotated anticlockwise from the positive -axis.
So, in the diagram, and and so
OK, so how do we find ?
- Look at the point on the unit circle where the angle is .
- Work out its coordinates by reflecting the first point in the -axis.
- Now write down and
- Divide as I did above to give
Do in exactly the same way.
Can you complete it now?