√1+cos A1−cos A = ?
(a) cosec A - cot A (b) cosec A + cot A
(c) cosec A cot A (d) none of these
LHS- √1+cos A1−cos A
Multiplying with √1+cos A on both numerator and denominator, we have,
=√1+cos A1−cos A×1+cos A1+cos A
=√(1+cos A)21−cos2 A
=1+cos A√sin2 A
=1+cos Asin A
=1sin A+cos Asin A
=cosecA + cotA
(b)