Straight Line Question 328

Question: Equations of the two straight lines passing through the point (3, 2) and making an angle of $ 45^{o} $ with the line $ x-2y=3, $ are [AMU 1978]

Options:

A) $ 3x+y+7=0 $ and $ x+3y+9=0 $

B) $ 3x-y-7=0 $ and $ x+3y-9=0 $

C) $ x+3y-7=0 $ and $ x+3y-9=0 $

D)None of these

Show Answer

Answer:

Correct Answer: B

Solution:

  • Slope of given line is $ \frac{1}{2}. $ Thus $ \tan 45^{o}=\pm \frac{m-\frac{1}{2}}{1+m.\frac{1}{2}} $
    Þ $ m=\pm 3 $ . Hence option (b) is correct.