If the image of y = 2cos (X3 + π 6) is translated according to vector a = (− π 4, − 2), the analytic expression of the translated image is () A. y＝2cos(x3+π4)−2B. y＝2cos(x3−π4)+2C. y＝2cos(x3−π12)−2D. y＝2cos(x3+π12)+2

If the image of y = 2cos (X3 + π 6) is translated according to vector a = (− π 4, − 2), the analytic expression of the translated image is () A. y＝2cos(x3+π4)−2B. y＝2cos(x3−π4)+2C. y＝2cos(x3−π12)−2D. y＝2cos(x3+π12)+2

Method 1 is defined by vector translation. If a pair of corresponding points P ′ (x ′, y ′), P (x, y) are arbitrarily selected on the image before and after translation, then a = (− π 4, − 2) = P ′, P = (x − x ′, y − y ′) {x ′ = x + π 4, y ′ = y + 2 can be substituted into the known analytical formula, and method 2 can be selected Unit: a