Consider the quadratic equation . Let be the set of all integral values of c for which one root of the equation lies in the interval and its other root lies in the interval . Then the number of elements in is:
- (A)18
- (B)12
- (C)10
- (D)11✓ Correct
Answer: (D)
Solution
Write . For one root in and the other in with the parabola opening upward (), we need , and . These give ; ; and . Hence , whose integer members are , giving values. The downward-opening case yields no overlap, so has elements.
JEE Main · 2019 · 10 Jan 2019 · Shift 1 · Single correct option