y = f(x) + n moves it n units up
y = f(x) - n moves it n units down
y = f(x + n) moves it n units left
y = f(x - n) moves it n units right
y = nf(x) stretches it in the y-direction
y = 1/n f(x) compresses it
y = f(nx) compresses it in the x-direction
y = f(1/n x) stretches it
y = −f(x) Reflects it about x-axis
y = f(−x) Reflects it about y-ax
Look at the picture.
Answer: y = 3cos(x - 0.5π) + 2