Question

Find an exact value.

Answer 1

Answer:

(√2 - √6) / 4

C. square root of two minus square root of six divided by four.

Step-by-step explanation:

sine of negative eleven pi divided by twelve.

We have :

sin(-11π/12)

sin((4 - 15)π / 12) = sin(4π/12 - 15π/12)

sin(4π/12 - 15π/12) = sin(π/3 - 5π/4)

Recall:

Angle difference formula:

sin(A - B) = sinAcosB - sinBcosA

Hence,

sin(π/3 - 5π/4) = sin(π/3) cos(5π/4) − sin(5π/4) cos(π/3)

From trigonometry:

sinπ/3 = √3/2

cos5π/4 = -√2/2

sin5π/4 = -√2/2

cos π/3 = 1/2

(√3/2) (-√2/2) − (-√2/2) (1/2)

-√6/4 - -√2/4

-√6/4 + √2/4

√2/4 - √6/4

(√2 - √6) / 4