Question 431148
Show an evaluation of sin 120 degrees using the trigonometric addition formulas. 
Show an evaluation of sin 120 degrees using the double-angle formulas...
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Addition formula:
sin(x+y)=sinxcosy+cosxsiny
sin120=sin(60+60)
           =sin60cos60+cos60sin60
           =(sqrt(3)/2)(1/2+(1/2)(sqrt(3)/2)
           =(sqrt(3)/2)

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Double angle formula:
Sin2x=2sinxcosx
Sin120=2sin60cos60
           =2(sqrt3/2)(1/2)
           =(sqrt3/2)