## Precalculus (6th Edition) Blitzer

The statement talks about a point t on the unit circle: $\sin t=-\frac{\sqrt{10}}{2}$ The round-off value of $-\frac{\sqrt{10}}{2}$ is $-1.59$, which is out of the range of the sine function. Therefore, the point t is not on the unit circle. Hence, the statement is false.