√1−sin A1+sin A = ?
(a) sec A + tan A (b) sec A - tan A
(c) sec A tan A (d) none of these
√1−sin A1+sin A
= √1−sin A1+sin A×√1−sin A1+sin A
= √(1−sin A)21−sin2 A
= √(1−sin A)2cos2 A
= 1−sin Acos A
= 1cos A−sin Acos A
=secA−tanA.