Known: as shown in the figure, m (3,2), n (1, - 1). Point P makes PM + PN shortest on the y-axis, and calculates the coordinates of point P

Known: as shown in the figure, m (3,2), n (1, - 1). Point P makes PM + PN shortest on the y-axis, and calculates the coordinates of point P

Draw a figure according to the meaning of the title, find out the symmetrical point n ′ of point n about y axis, connect Mn ′, and the intersection point with y axis is the obtained point P, ∵ n (1, - 1), ∵ n ′ (- 1, - 1). Let the analytic expression of straight line Mn ′ be y = KX + B, substitute m (3,2), n ′ (- 1, - 1) to get: 3K + B = 2 − K + B = − 1, the solution is k = 34B