Begin with `f(x)=sinx` .
(1) A vertical compression of 2/3 is achieved by multiplying the function by 2/3. This reduces the amplitude by a factor of 2/3.
Thus the leading coefficient is 2/3.
(2) A reflection in the x-axis is achieved by multiplying f(x) by -1.
Thus the leading coefficient is now -2/3.
(3) A vertical translation (shift) up of 15 units is achieved by adding 15 to f(x).
Therefore, the required function is `f(x)=-2/3sinx+15` .