Question bank/JEE Main/Mathematics
JEE MainMathematics
If the roots of the quadratic equation x2 + 6x + b = 0 are real and
distinct and they differ by atmost 4 then the range of values of b is
Show answer and solution
α - β |2 ≤ 16
(α + β)2 - 4αβ ≤ 16
36 - 4b 4b ⇒b
5....(1)
Also roots are real ⇒D > 0 ⇒36 - 4b > 0 ⇒b < 9....(2)
From (1) and (2) b
(α + β)2 - 4αβ ≤ 16
36 - 4b 4b ⇒b
5....(1)
Also roots are real ⇒D > 0 ⇒36 - 4b > 0 ⇒b < 9....(2)
From (1) and (2) b
Source: Grass-G / M-01 Mathematics Paper-1.docx
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