Answer:
y = -(3/4)sin(2(x-3))
Step-by-step explanation:
You want the equation of a sine function with amplitude 3/4, period pi, shifted right 3 units, and reflected across the x-axis.
Transformations
For a function f(x), it is scaled by a factor of k by ...
k·f(x)
It is reflected across the x-axis by changing its sign:
-f(x)
The function is expanded horizontally by a factor of k by ...
f(x/k)
And shifted right by k units by ...
f(x -k)
Application
You want a sine function scaled vertically by a factor of 3/4, and reflected across the x-axis. Those transformations will give you ...
y = -(3/4)sin(x)
You want to compress the period from 2π to π, using an expansion factor of 1/2. That transformation in addition to the ones already noted will give you ...
y = -(3/4)sin(x/(1/2)) = -(3/4)sin(2x)
Finally, you want to shift the function right by 3 units, which calls for replacing x by (x-3):
y = -(3/4)sin(2(x-3))
