You can put this solution on YOUR website! What is the exact value of sin 19π/12?
(19π/12)=(10π/12+9π/12)=(5π/6+3π/4)
sin(19π/12)=sin(5π/6+3π/4)
sin addition formula:
sin(s+t)=sin s cos t + cos s sin t
s=5π/6
t=3π/4
Both angles in quadrant II where sin>0, and cos<0
sin(19π/12)=sin(5π/6+3π/4)
sin(19π/12)=sin(5π/6)cos(3π/4)+cos(5π/6)sin(3π/4)
sin(19π/12)=1/2*-√2/2+-√3/2*√2/2
sin(19π/12)=-√2/4+-√6/4=-(√2+√6)/4
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