Ok, I have to take an accuplacer, I was doing a practice test online to prepare. I was given the equation:

$\displaystyle \sin(2\theta)+3=4$

I need to find $\displaystyle \theta$

$\displaystyle \sin(2\theta)=1$

When the sine of an angle is equal to one on $\displaystyle [0,2\pi]$ then the angle must be equal to $\displaystyle \frac{\pi}{2}$ right? So I have:

$\displaystyle 2\theta=\frac{\pi}{2}$

$\displaystyle \theta=\pi$

The practice test I as doing is mulitple choice. Of course $\displaystyle \pi$ was actually the wrong answer . Where am I going wrong here?