1
JEE Main 2019 (Online) 12th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
If $$\lambda $$ be the ratio of the roots of the quadratic equation in x, 3m2x2 + m(m – 4)x + 2 = 0, then the least value of m for which $$\lambda + {1 \over \lambda } = 1,$$ is
A
$$ - 2 + \sqrt 2 $$
B
4$$-$$3$$\sqrt 2 $$
C
2 $$-$$ $$\sqrt 3 $$
D
4 $$-$$ 2$$\sqrt 3 $$
2
JEE Main 2019 (Online) 12th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
Let P = $$\left[ {\matrix{ 1 & 0 & 0 \cr 3 & 1 & 0 \cr 9 & 3 & 1 \cr } } \right]$$ and Q = [qij] be two 3 $$ \times $$ 3 matrices such that Q – P5 = I3.

Then $${{{q_{21}} + {q_{31}}} \over {{q_{32}}}}$$ is equal to :
A
15
B
9
C
135
D
10
3
JEE Main 2019 (Online) 12th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
The maximum value of 3cos$$\theta $$ + 5sin $$\left( {\theta - {\pi \over 6}} \right)$$ for any real value of $$\theta $$ is :
A
$$\sqrt {34} $$
B
$$\sqrt {31} $$
C
$$\sqrt {19} $$
D
$${{\sqrt {79} } \over 2}$$
4
JEE Main 2019 (Online) 12th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
An ordered pair ($$\alpha $$, $$\beta $$) for which the system of linear equations
(1 + $$\alpha $$) x + $$\beta $$y + z = 2
$$\alpha $$x + (1 + $$\beta $$)y + z = 3
$$\alpha $$x + $$\beta $$y + 2z = 2
has a unique solution, is :
A
(–3, 1)
B
(1, –3)
C
(–4, 2)
D
(2, 4)
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