Math, asked by manjushukla499, 2 months ago

evaluate (without using table) : b) cos13°×cosec77°​

Answers

Answered by 11Prem11
1

So we know,

Sin A = cos (90-A)

so in cos 13 we can write it as sin (90-13)

= sin 77

and cosec A = 1/ sin a

So

cos 13 × cosec 77

= sin 77 × 1/sin 77

= 1

So , cos13°×cosec77° = 1

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