Evaluate: sin 25° cos 65° + cos 25° sin 65°

Asked by Abhisek | 1 year ago |  69

##### Solution :-

sin 25° cos 65° + cos 25° sin 65°

To simplify this, convert some of the sin functions into cos functions

and cos function into sin function and it becomes,

= sin(90°-25°) cos 65° + cos (90°-65°) sin 65°

= cos 65° cos 65° + sin 65° sin 65°

= cos265° + sin265° = 1 (since sin2A + cos2A = 1)

Therefore, sin 25° cos 65° + cos 25° sin 65° = 1

Answered by Pragya Singh | 1 year ago

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