how to find the first three zeros to the right of origin in a sinusoidal function?

Answer 1

Good question. If you have
y=sin(x) + 2,
then there aren't any.

If you have cos(kx) the period is 2pi/k

How about sin(x²)? That's sinusoidal, with decreasing period.

In short, you question cannot be answered without further information