BPSC 56th-59th Exam Prelims 15 Mar 2015 Solved Paper

© examsiri.com

Question : 128 of 150

Marks: +1, -0

The angle between two lines

3x + y – 7 = 0

and

x + 2y + 9 = 0

will be

60°
45°
30°
90°

Solution:

3 x+y-7=0

⇒ y=-3 x+7

hence slope

=-3= {m}

Again,

x+2 y+9=0

⇒ 2 y=-x-9

⇒ y=\;{-1}/{2} x-\;{9}/{2}

∴

slope

=-\;{1}/{2}= {m}_{2}

∴ \tan θ=± \;{m_{1}-m_{2}}/{1+m_{1} m_{2}}

=\;{-3+{1}/{2}}/{1+\;{3}/{2}}=± 1

∴ \tan θ=\tan 45^{∘} ⇒ θ=45^{∘}

Hence, angle will be

45^{∘}

© examsiri.com

Go to Question:

Prev Question

Next Question