Straight Line Question 19

Question: The angle between the lines $ 2x-y+3=0 $ and $ x+2y+3=0 $ is [Kerala (Engg.) 2002]

Options:

A) $ 90^{o} $

B) $ 60^{o} $

C) $ 45^{o} $

D) $ 30^{o} $

Show Answer

Answer:

Correct Answer: A

Solution:

  • Angle between two lines is given by $ \tan \theta =\frac{m_1-m_2}{1+m_1m_2} $ Given $ m_1=\frac{-1}{2}, $ $ m_2=2 $

$ \therefore m_1m_2=-1 $ . So the lines are perpendicular i.e., $ \theta =90{}^\circ $ .