# How do you find the period and amplitude of y=3sin2x?

Amplitude is the value of $a$, which is $3$ in this case. This means the vertical distance from the centre line to the max/min is $3$ units.
The period is given by $2 \frac{\pi}{b} = \frac{2 \pi}{2} = \pi$. Which means that it takes the function $\pi$ units to repeat itself.