If the distance from the moving point P to the point F (1,1) and the straight line 3x + y-4 = 0 is equal, then the trajectory equation of point P is () A. 3x+y-6=0B. x-3y+2=0C. x+3y-2=0D. 3x-y+2=0

If the distance from the moving point P to the point F (1,1) and the straight line 3x + y-4 = 0 is equal, then the trajectory equation of point P is () A. 3x+y-6=0B. x-3y+2=0C. x+3y-2=0D. 3x-y+2=0


If point F (1,1) is on the straight line 3x + y-4 = 0, then the trajectory of point P is a straight line passing through point F (1,1) and perpendicular to the known straight line. Because the slope of the straight line 3x + y-4 = 0 is - 3, the slope of the straight line is 13. From the oblique form of the point, we know that the trajectory equation of point P is Y-1 = 13 (x-1), that is, x-3y + 2 = 0, so we choose B



If the distance from point P to point F (4,0) is less than the distance from point P to line x + 5 = 0 by 1, then the trajectory equation of moving point P is______ .


The distance from point P to point F (4,0) is 1 less than the distance from point P to line x + 5 = 0, and the distance from point P to line x = - 4 is equal to the distance from point P to point (4,0). According to the definition of parabola, the trajectory of point P is a parabola with point (4,0) as the focus and line x = - 4 as the guide line, and the trajectory equation of point P is y2 = 16x