JEE Advanced2013MathematicsStraight LinesActual
For a > b > c > 0, the distance between (1, 1) and the point of intersection of the lines ax + by + c = 0 and bx + ay + c = 0 is less than 2 2 .Then
Options
- Aa + b - c > 0
- Ba - b + c < 0
- Ca - b + c > 0
- Da + b - c < 0
Correct answer
A. a + b - c > 0
Step-by-step solution
a - b x + b - a y = 0 ⇒ x = y ⇒ Point of intersection - c a + b , - c a + b Now using distance formula between two points d = x 1 - x 2 2 + y 1 - y 2 2 ⇒ 1 + c a + b 2 + 1 + c a + b 2 < 2 2 ⇒ 2 a + b + c a + b < 2 2 ⇒ a + b + c a + b < 2 ⇒a + b + c < 2 a + b ⇒ a + b - c > 0