to the curve $\displaystyle y = \frac{1}{\sqrt3} \sin 3x$at the origin make with the x-axis?

I found that $\displaystyle y' = \sqrt3 \cos 3x$ so when $\displaystyle x = 0$, $\displaystyle \sqrt3 \cos 3(0) = \sqrt3*1 = \sqrt3$

I feel like I should be ending up with $\displaystyle \frac{\sqrt3}{2}$