the maximum value of y is 6 when x=0, y=6
the period of the graph is equal to PIE
A,B and C are positive and C is less than 2PIE
The maximum value of y= A sin(Bx+ C) is A.
If for some x, Bx+ C= 0, the when (subtract the first equation from the second) . Since we are told that the period is , we can take to get .
Finally, the maximum occurs at . Since we are told that it happens when x= 0, we must have .