Question

In which quadrant is sin negative and cos negative?OA. IB. IIIOC. IVOD. II

Answer 1

In order to see where the sin and cos are negative, we use the definition and the cartesian plane,

then,

$sin\theta=\frac{y}{r};cos\theta=\frac{x}{r}$

then, by definition r is always going to be positive due to the Pythagorean theorem.

Then, the sin and cos are negative in the quadrant where both x and y are negative.

Answer:

The sin and cos are negative in the third quadrant.