Find the area of the triangle formed by the lines y=m1x+c1,y=m2x+c2 and x = 0
Let the sides AC, AB and BC of △ ABC be represented by the equations:
m1x−y+c1=0.....(i)
m2x−y+c2=0.....(ii)
x=0.....(iii)
On solving (i) and (ii) by cross multiplication, we have,
x(−C2+C1)=y(m2c1−m1c2)=1(−m1+m2)
⇒x=(c1−c2)(m2−m1) and y=(m2c1−m1c2)(m2−m1)
Thus, the lines AC and AB intersect at A (c1−c2m2−m1,m2c1−m1c2m2−m1)
On solving (ii) and (iii), we get B(0,c2).
On solving (i) and (ii), we get C(0,c1)
∴ area of △ABC is given by,
A =12∣∣(c1−c2)(m2−m1).(c2−c1)+0+0∣∣
=12(c1−c2)2|m1−m2|