find the exact value of sin(-5π/12)

Answer 1

Hi Roz A.,

We can use the addition/subtraction formulas to find sin(-5π/12).

π/4 - 2π/3 = -5π/12, (you can use other angles to subtract to get -5π/12 as long as they add or subtract to your given angle).

Then sin(-5π/12) = sin(π/4 - 2π/3), then use the subtraction formula sin(u - v) = sin(u)cos(v) - cos(u)sin(v).

sin(π/4)cos(2π/3) - cos(π/4)sin(2π/3)

[√(2)/2]*[-1/2] - [√(2)/2]*[√(3)/2]

-√(2)/4 - √(6)/4

I hope this helps, Joe.