It is always important to look at a view critical values.
what happens to our function when x = 0 ?
what happens when y = 0
what happens to the tangent curve at pi/4 or pi/2
this should help you on your way.
again you have to look at some critical points,
the function f(x) is of the form f(x) = Asin(bx) + C
so what happens when x = 0 ?
what about when f(x) = 0
x = sin(pi/2) ?
x = sin(pi/6) ?
you need to show some working yourself