Find the condition in a,b such that the portion of the line ax+by=1, intercepted between the lines ax+y=0 and x + by=0 sustains a right angle at origin.

Options

A. a =b
B. a+b=0
C. a=2b
D. 2a=b

Answer

B

Explanation

Lines ax+y=0 and x+by=0 intersect at O(0,0).

Hence, if AB subtends right angle at O(0,0), then ax+y=0 and x+by=0 are perpendicular to each other. So,
`(-a)(-(1)/(b))=-1`
or a+b=0