Question

3sin70°sec20°+ 2sin49° sec 51° is​

Answer 1

Step-by-step explanation:

3sin70°sec20°+ 2sin49° sec 51°

=3sin70°cosec(90°-20°)+ 2sin49° cosec (90°-51°)

=3sin70°cosec70°+ 2sin49° cosec 49°

= 3 x 1 +2 x 1

= 3 + 2

= 5

Reasons:

$cosec (90\degree - \theta) = sec \theta\\ sin \theta \times cosec \theta = 1$