As sin(90) =1
We have A+B =90°
As cos (30) =√3/2
So we also have A+B=30,
So as both cannot happen at the same time, I think your question is
If sin (A+B ) = 1 , cos ( A-B ) = √3/2 0° <A+ B<90° then find A and B
Sin(A+B)=1
cos(A-B)=√3/2
We know siin90=1
A+B=90 _ _ _ _(1)
cos (A-B)=√3/2
A-B=cos-¹ (√3/2)
We know cos-¹ (√3/2)=30
A-B=30 _ _ _ _ _ (2)
Solve (1) & (2)
A+B=90----(1)
A-B=30 ----(2)
add (1) and (2)
2A=120
A=60°
Sub A in (1)
=>B =90 -A =90-60
=30°