Arun
Last Activity: 6 Years ago
b is in (2, ∞)
Justification:
i) The given line is: a²x + (ab)y + 1 = 0
ii) Plugging (0,0), it is: 1; thus origin (0, 0) is above the line.
So the point (1, 1) also has to be above the line;
==> a² + ab + 1 > 0
Taking this a quadratic in a, a is in R, if and only if its discriminant is ≥ 0
==> b ≥ 2 [as b is given > 0, only positive value is considered and b ≤ -2 is rejected]
