Use a sum or difference identity to find exact value of sin 255.

Question

Mathematics

Noemi Ruiz

14 June, 12:28

Use a sum or difference identity to find exact value of sin 255.

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Answers (1)

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Kelsey · Answer 1

Sin (x + y) = sin x cos y + cos x sin y

sin 255

= sin (210 + 45)

= sin 210 cos 45 + cos 210 sin 45

= (-1/2) (√ (2) / 2) + (-√ (3) / 2) (√ (2) / 2)

= - √ (2) / 4 + (-√ (6) / 4)

= - √ (2) / 4 - √ (6) / 4

= (-√ (2) - √ (6)) / 4