JEE Main | 2014Quadratic EquationMedium
Question
Let α and β be the roots of equation px2 + qx + r = 0, p ≠ 0. If p, q, r are in A.P. and 
, then the value of |α - β| is
, then the value of |α - β| isOptions
A.
B.
C.
D.
Solution
∵ p, q, r are in AP
2q = p + r ......(i)
Also
⇒
= 4
= 4 ⇒ q = - 4r ......(ii)
From (i)
2(-4r) = p + r
p = - 9r
q = - 4r
r = r
Now |α - β| =
2q = p + r ......(i)
Also
⇒
= 4= 4 ⇒ q = - 4r ......(ii)From (i)
2(-4r) = p + r
p = - 9r
q = - 4r
r = r
Now |α - β| =
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