Unformatted text preview: THE TWOPOIN T FORMULA If a line passes through two given points (x1 , yl) and (x2 ,y2 ), then the
EQUATION of the line can be determined using this one formula: This formula is identical to y—y1 = m(x —x1), y2—y1 Where the m is replaced with
x2“x1 Example: Find the equation of the line passing through (2, —3) and (4 , 1). Solution: Let (x1,y1.) = (2, —3) and (x2,y2) = (4,1) y2—y1
y—y1= (x—xl)
x2—x1 1——3
m —— —2
beco es y 3 4_2 (x ) y+3 2(x—2)
y+3 2x—4
y 2x—7. ALTERNATIVELY the equation of the line can be determined by
using two concepts already covered: yz—yi (i) Find the gradient by using m = .
x2_x1 (ii) Determine the equation by using y —y1 = m(x —x 1). ...
View
Full Document
 Winter '10
 golishr

Click to edit the document details