解题思路:把y=sin(2x+[π/3])化为cos[2(x-[π/12])],故把cos[2(x-[π/12])]的图象向左平移[π/12]个单位,即得函数y=cos2x的图象.
y=sin(2x+[π/3])=cos[[π/2]-(2x+[π/3])]=cos([π/6]-2x)=cos(2x-[π/6])=cos[2(x-[π/12])].
故把cos[2(x-[π/12])]的图象向左平移[π/12]个单位,即得函数y=cos2x的图象,
故选 A.
点评:
本题考点: 函数y=Asin(ωx+φ)的图象变换.
考点点评: 本题考查诱导公式,以及y=Asin(ωx+∅)图象的变换,把y=sin(2x+[π/3])化为cos[2(x-[π/12])],是解题的关键.