Question 1033152
sin(x+π/3) = cos2x 
proposed in the book, namely:
x= π/18+2kπ/3 V x= -π/6+2kπ 
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since sin(K) = cos((pi/2)-K) you can make a change on the left side::
cos((pi/2)-(x+(pi/3))) = cos(2x)
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(pi/2)-x-(pi/3) = 2x
3x = [(3pi-2pi)/6]
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x = pi/18 + 2kpi ; x = -pi/18 + 2kpi
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Cheers,
Stan H.