Answer
Quadrant II
Work Step by Step
By Definition I-
$\sin\theta$ =$ \frac{y}{r}$
Given $\sin\theta$ is positive, hence y is positive as r being distance can not be negative. 'y' is positive in Quadrant I and II.
$\cos\theta$ =$ \frac{x}{r}$
If $\cos\theta$ is negative, then x is negative as r being distance can not be negative. x is negative in Quadrant II and III only.
Concluding from both of the above statements, both can be true only when terminal side lies in Quadrant II
