Determine all points of intersection: y=cosx and y=sinx in the first quadrant

So the question is asking to determine all points of intersection, and base on my research and further computation about the said question, the possible answer would be y=cos(x), sin(x)=cos(x),  sin2(x)=cos2(x), sin2(x)=1−sin2(x),  sin2(x)+sin2(x)=1,  2sin2(x)=1, sin2(x)=1/2, sin(x)=√1/2, sin(x)=√2/2. I hope this would help 

A= b/2 because u simplying both sides of equation