## Trigonometry 7th Edition

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