Given sin (13y-5) = cos (2y+5)
We have a formula regarding complementary angles that is given as follows :-
If sin(A) = cos(B), then A + B = 90 degrees.
where A and B are complementary angles.
Comparing it with given information, we get A = (13y-5) and B = (2y+5).
So the sum of two angles A = (13y-5) and B = (2y+5) would be 90 degrees.
(13y-5)° + (2y+5)° = 90°
13y + 2y - 5 + 5 = 90°
15y = 90°
y = 6°
Hence, final answer is y = 6 degrees.