Question

Solve this......................... ​

Answer 1

TO FIND :- cos 57° × cosec 33°

SOLUTION :-

$\cos(57) \times \cosec(33) \\ \\ \\ = \cos(57) \times \sec(90 - 33) \\ \\ \\ = \cos(57) \times \sec(57) \\ \\ \\ = \cos(57) \times \frac{1}{ \cos(57) } \\ \\ \\ = 1 \: \: \: (ans)$

SOME IMPORTANT IDENTITIES :-

sin A = 1/cosec A

cos A= 1/sec A

tan A= 1/cot A

cot A = 1/tan A

sec A = 1/cos A

cosec A = 1/sin A

sinA = cos(90 - A)

cosA = sin ( 90 - A)

tan A = cot(90 - A)

cot A = tan (90 - A)

sec A = cosec (90 - A)

cosec A = sec (90 - A)