1
WB JEE 2020
+1
-0.25
Let A = $$\left( {\matrix{ {3 - t} \cr { - 1} \cr 0 \cr } \matrix{ {} \cr {} \cr {} \cr } \,\matrix{ 1 \cr {3 - t} \cr { - 1} \cr } \matrix{ {} \cr {} \cr {} \cr } \matrix{ 0 \cr 1 \cr 0 \cr } } \right)$$ and det A = 5, then
A
t = 1
B
t = 2
C
t = $$-$$ 1
D
t = $$-$$ 2
2
WB JEE 2020
+1
-0.25
Let $$A = \left[ {\matrix{ {12} & {24} & 5 \cr x & 6 & 2 \cr { - 1} & { - 2} & 3 \cr } } \right]$$. The value of x for which the matrix A is not invertible is
A
6
B
12
C
3
D
2
3
WB JEE 2020
+1
-0.25
Let $$A = \left( {\matrix{ a & b \cr c & d \cr } } \right)$$ be a 2 $$\times$$ 2 real matrix with det A = 1. If the equation det (A $$-$$ $$\lambda$$I2) = 0 has imaginary roots (I2 be the identity matrix of order 2), then
A
(a + d)2 < 4
B
(a + d)2 = 4
C
(a + d)2 > 4
D
(a + d)2 = 16
4
WB JEE 2020
+1
-0.25
If $$\left| {\matrix{ {{a^2}} & {bc} & {{c^2} + ac} \cr {{a^2} + ab} & {{b^2}} & {ca} \cr {ab} & {{b^2} + bc} & {{c^2}} \cr } } \right| = k{a^2}{b^2}{c^2}$$,

then K =
A
2
B
$$-$$ 2
C
$$-$$ 4
D
4
EXAM MAP
Medical
NEET