Question

what can you say about the values of sinA and cos A,as the value of angle A increases from o to 90?
if A>B,then sin A > sin B. is it true?
if A>B,then cos A> cos B,is it true?

Answer 1

Sin A > Sin B is true as we see

Sin 0 =  0
Sin 30 = 0.5
Sin 45 = 0.707
Sin 60 = 0.866
Sin 90 = 1

Answer 2

In the interval 0 to 90°,

- sin is an increasing function i.e. as the value of angle(Ф) increases, the value of   function sin(Ф) increases . So if A>B, then Sin A > sin B.
  So the statement  is true.

- cos is a decreasing function i.e. as the value of angle(Ф) increases, the value of   the function cos(Ф) decreases. So if A>B, then cos A < cos B.
  So the statement is false.