I don't what they are trying to say. PLEASe help me

IfAfalls on Quadrant II andBfalls in Quadrant III, then what the sign of cos(A+B).

its is greater than 0 or less than 0.

and then another example just like the same.

If A falls on Quadrant II, and B falls on Quadrant III, then what is the sign of sin(A-B)

it's is greater than 0 or less than 0.