Question

without using trigonometric tables evaluate sin 35 degree into cos 55 degree + cos 35 degree into sin 55 degree upon cos square 10 degree minus tan square 80 degree​

Answer 1

Step-by-step explanation:

sin35×cos (90-35)+cos35×sin (90-35)

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cos2 10-tan2 80

=1

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-tan2 10

=-cot2 10