Answer:
Option 2. y = 3 cos πx is the answer.
Step-by-step explanation:
If the function is in the standard form of y = acos(bx+c) or y = asin(bx+c)
Then period of the given function will be = 2π/b
1) For y = cos(x - π/2)
Therefore period of the function will be = 2π/1 = 2π
2) For y = 3cos πx
Period = 2π/π = 2
Correct option.
3) y = 2 sin 3x
Period of the function = 2π/3
4). y = -4sin 2x
Period of the function = 2π/2 = π
So option 2 is the answer.
