√(1+sinA)−√(1−sinA)=−2cos(A/2)
A
√1+sinA - √1−sinA=−2cos(A2)
⇒|cosA2+sinA2|−|cosA2−sinA2|=−2cosA2
5π2<A<7π2
The value of cos−1(cos3π2) is
(a) π2 (b) 3π2 (c) 5π2 (d) 7π2