Answer:
sin is only positive in 1st and 2nd quadrants
Step-by-step explanation:
As you may know, sine is defined as y-term or value in (x, y). You can go see a unit circle.
Remember that sine is y while cosine is x.
Since sine is y, It'd be a horizontal line. And since it's a horizontal line, it intersects two points in a unit circle.
Q1 and Q2 both are positive while Q3 and Q4 are negative.
