Answer:
π
Step-by-step explanation:
The standard form of the sine function is
y = a sin(bx + c)
where a is the amplitude, period = [tex]\frac{2\pi }{b}[/tex] and
phase shift = - [tex]\frac{c}{b}[/tex]
here b = [tex]\frac{1}{2}[/tex], c = - [tex]\frac{\pi }{2}[/tex]
phase shift = - [tex]\frac{-\frac{\pi }{2} }{\frac{1}{2} }[/tex]
= [tex]\frac{\pi }{2}[/tex] × 2 = π