write the equation of a sine function that has the following characteristics amplitude 9, period 6pi and phase shift -1/4

y=A*sin[B(x+C)] +D

NOTE: the B is outside the bracket

A=amplitude

period is 2pi/B

Phase shift is -C

vertical shift is D

http://www.youtube.com/watch?v=BQ4QzTcG90g

y = 9sin[(1/3)(x +1/4)] = 9sin[(4x + 3)/12]

Here's the graph