NCERT Class 11 Mathematics Solutions: Chapter 10 – Straight Lines Miscellaneous Exercise 10 Part 10 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Angle between Two Lines

1. If the lines are equally inclined to the line , find the value of .


The equations of the given lines are

… eq (1)

… eq (2)

… eq (3)

Slope of line

Slope of line

Slope of line

It is given that lines (1) and (2) are equally inclined to line (3) .

This means that the angle between lines (1) and (3) equals the angle between lines (2) and (3) .


If then

, which is not real.

Hence, this case is not possible.

If , then

So, the required value of is