Foot of perpendicular short trick
Foot of Perpendicular from a given point on a line Let P : (x1 , y1) be the point and L : (ax + by + c = 0) be the line . Let (x , y) be the foot of perpendicular. Method 1 : Let '' m1 '' be the slope of line '' L ''. m1 = -a / b Now , we make a line perpendicular to '' L '' passing through '' P ''. So, slope of that line is (-1 / m1) and passing point point is (x1 , y1). We can find line equation by using point slope form. And, then find the intersection point of given line and above line. But this method is time consuming. Method 2 : Example : Let 2x + y = 3 be the line and (1, 2) be the point . So, L : 2x + y - 3 = 0 { a = 2 ; b = 1 ; c = -3} P : (1 , 2) {x1 = 1 ; y1 = 2} Now, x - 1 = y - 2 = - 1 2 1 5 x - 1 ...