Question
Question: If the lines x = a + m, y = –2 and y = mx are concurrent, the least value of \|a\| is...
If the lines x = a + m, y = –2 and y = mx are concurrent, the least value of |a| is
A
0
B
√2
C
2√2
D
None of these
Answer
2√2
Explanation
Solution
Since the lines are concurrent –2 = m(a + m)
⇒ m2 + am + 2 = 0.
Since m is real, a2 ≥ 8, |a| ≥2√2.
Hence the least value of |a| is 2√2