NDA Maths Mock Test – 01 – Q19

If both the roots of the equation x² – 4kx + 4k² – 4 = 0 lies between -1 and 3, then which of the following is correct?

• 1/2 < k < 5/2
• No value of k
• -3/2 < k < 1/2
• -1 < k < 2

‘ R∞ts of the equation ‘
= x² kx +4K% 4 =O are
1 —(—4k)£/ (4k) 4 (4° 4) x1
T= 2×1 1
_ 4k=V16K7-16k7+16
– 2
1 _ 4k+16 1
2
=H — ok +2 !
‘ Since, gi√en r∞ts lies between -1 and 3. Therefore, -1 <2k +2 <3 and -1<2k-2<3 i
‘ = -3<2khon a
‘ ⇒ FP Hence, no √alue of k exist.