InterviewSolution
Saved Bookmarks
| 1. |
Let o lt p lt q and a ne 0 such that the equation px^(2) +4 lambda xy +qy^(2) +4a (x+y +1) = 0 represents a pair of straight lines, then a can lie in the interval |
|
Answer» `(-oo,oo)` `p.q.4A +2.2a.2a.2lambda -p.4a^(2) -q.4a^(2)-4a.4lambda^(2) =0` `rArr 4 lambda^(2) -4a lambda + {(p+q)q-pq} =0 ( :' q ne 0)` Since, `lambda in R, 16a^(2) - 4.4 {(p+q)a-pq} ge 0` or `(a-p)(a-p) ge 0` `:. a le p` or `a ge q` |
|