Math Help - stuck on this problem

Write an equation using the sine function which goes through the points (5pie/3 , 2) and (10pie/3 , -1) Next write an equation using cosine going through the same two points.

Is the answer

Y=3 sin(x)+.5
Y=-3 cos(x)+.5

I don't think these answers are right so could someone help me?

The points are in polar coordinates.

Use y = r sin(angle) to write your equations.

I can't use angles. I have to do it in form y=sin(x)+b