Find the tangent of the angle between the lines which have intercepts 3, 4 and 1, 8 on the axes respectively.
Line1 is x3+y4=1
i.e. 4x+3y=12
Line2 is x1+y8=1
i.e. 8x+y=8
Slope of line1 and line2 is −43 and −81
respectively.
Thus, tan θ=∣∣m1−m21+m1m2∣∣
=∣∣ ∣∣−43−(−8)1+(−43)(−8)∣∣ ∣∣
=∣∣∣−43+81+323∣∣∣=∣∣−4+243+32∣∣
=∣∣2035∣∣=47
Thus, tan θ=47