Q26 of 59 Page 178

The tangent of angle between the lines whose intercepts on the axes are a, – b and b, – a, respectively, is

Let the first equation of line having intercepts on the axes a, -b is



bx – ay = ab …(i)


Let the second equation of line having intercepts on the axes b, -a is




ax – by = ab …(ii)


Now, we find the slope of eq. (i)


bx – ay = ab


ay = bx – ab



Since, the above equation is in y = mx + b form


So, the slope of eq. (i) is



Now, we find the slope of eq. (ii)


ax – by = ab


by = ax – ab



Since, the above equation is in y = mx + b form


So, the slope of eq. (i) is



Let θ be the angle between the given two lines.



Putting the values of m1 and m2 in above eq., we get






Hence, the required angle is


Hence, the correct option is (c)

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