Tiêu đề Maths XI - Straigth lines - Angle between two lines .ppt.ppt ✅

Proof The lines passing through the origin and parallel to the given lines are a1x+b1y=0→(1) a2x+b2y=0→(2) Let θ1, θ2 be the inclinations of (1) and (2) respectively (θ1> θ2) O L M y P Q 2 1 x θ1 θ2
Now θ is an angle between (1) and (2) Thus θ= θ1- θ2 Since P(-b1,a1) satisfies eq. (1), the point lies on (1) Similarly Q(-b2,a2) lies on (2) O L M y P Q 2 1 x θ1 θ2 θ Let L, M be the projections of P, Q respectively on x-axis