Y =矢量a?向量B = COS mm 2 X+源代碼3 sinxcosx =(1+cos2x)/2+源代碼3/2 sin2x =(1/2的單調遞增函數y)+sin(2x+π/6);
當2kπ-π/2
即y單調遞增的時間區間[Kπ-π/ 3,kπ+π/6];