Let A = {X = (x, y, z)T: PX = 0 and
x2 + y2 + z2 = 1} where
P = \left[ {\matrix{
1 & 2 & 1 \cr
{ - 2} & 3 & { - 4} \cr
1 & 9 & { - 1} \cr
} } \right],
then the set A :
Mathematicsmatrices-and-determinants2020medium
If Δ = \left| {\matrix{
{x - 2} & {2x - 3} & {3x - 4} \cr
{2x - 3} & {3x - 4} & {4x - 5} \cr
{3x - 5} & {5x - 8} & {10x - 17} \cr
} } \right| =
Ax3 + Bx2 + Cx + D, then B + C is equal to :
Mathematicsmatrices-and-determinants2020medium
Let α be a root of the equation x2 + x + 1 = 0 and the
matrix A = {1 \over {\sqrt 3 }}\left[ {\matrix{
1 & 1 & 1 \cr
1 & \alpha & {{\alpha ^2}} \cr
1 & {{\alpha ^2}} & {{\alpha ^4}} \cr
} } \right]
then the matrix
A31 is equal to
Mathematicsmatrices-and-determinants2020medium
If the system of linear equations
2x + 2ay + az = 0
2x + 3by + bz = 0
2x + 4cy + cz = 0,
where a, b, c ∈ R are non-zero distinct; has a non-zero solution, then:
Mathematicsmatrices-and-determinants2020medium
Let A = [aij] and B = [bij] be two 3 × 3 real matrices such that bij = (3)(i+j-2)aji, where i, j = 1, 2, 3.
If the determinant of B is 81, then the determinant of A is:
Mathematicsmatrices-and-determinants2020medium
For which of the following ordered pairs (μ, δ),
the system of linear equations
x + 2y + 3z = 1
3x + 4y + 5z = μ
4x + 4y + 4z = δ
is inconsistent ?
Mathematicsmatrices-and-determinants2020medium
The system of linear equations
λx + 2y + 2z = 5
2λx + 3y + 5z = 8
4x + λy + 6z = 10 has
Mathematicsmatrices-and-determinants2020medium
If the matrices A = \left[ {\matrix{
1 & 1 & 2 \cr
1 & 3 & 4 \cr
1 & { - 1} & 3 \cr
} } \right],
B = adjA and
C = 3A, then {{\left| {adjB} \right|} \over {\left| C \right|}} is equal to :
Mathematicsmatrices-and-determinants2020medium
If for some α and β in R, the intersection of the
following three places
x + 4y – 2z = 1
x + 7y – 5z = b
x + 5y + αz = 5
is a line in R3, then α + β is equal to :
Mathematicsmatrices-and-determinants2020medium
The following system of linear equations
7x + 6y – 2z = 0
3x + 4y + 2z = 0
x – 2y – 6z = 0, has
Mathematicsmatrices-and-determinants2020medium
Let S be the set of all λ∈ R for which the system
of linear equations
2x – y + 2z = 2
x – 2y +
λz = –4
x +
λy + z = 4
has no solution. Then the set S :
Mathematicsmatrices-and-determinants2020medium
Let A be a 2 × 2 real matrix with entries from
{0, 1} and |A|
= 0. Consider the following two
statements :
(P) If A = I2
, then |A| = –1
(Q) If |A| = 1, then tr(A) = 2,
where I2
denotes 2 × 2 identity matrix and tr(A)
denotes the sum of the diagonal entries of A. Then :
Mathematicsmatrices-and-determinants2020medium
Let a, b, c ∈ R be all non-zero and satisfy
a3 + b3 + c3 = 2. If the matrix
A = \left( {\matrix{
a & b & c \cr
b & c & a \cr
c & a & b \cr
} } \right)
satisfies ATA = I, then a value of abc can be :
Mathematicsmatrices-and-determinants2020easy
If A = \left( {\matrix{
2 & 2 \cr
9 & 4 \cr
} } \right) and I = \left( {\matrix{
1 & 0 \cr
0 & 1 \cr
} } \right) then 10A–1 is
equal to :
Mathematicsprobability2020medium
Let EC denote the complement of an event E.
Let E1
, E2
and E3
be any pairwise independent
events with P(E1) > 0
and P(E1 ∩ E2 ∩ E3) = 0.
Then P(E2C∩E3C/E1) is equal to :
Mathematicsprobability2020medium
The probabilities of three events A, B and C are
given by
P(A) = 0.6, P(B) = 0.4 and P(C) = 0.5.
If P(A∪B) = 0.8, P(A∩C) = 0.3, P(A∩B∩C) = 0.2,
P(B∩C) = β
and P(A∪B∪C) = α, where
0.85 ≤α≤ 0.95, then β lies in the interval :
Mathematicsprobability2020medium
Out of 11 consecutive natural numbers if three numbers are selected at random (without repetition), then the probability that they are in A.P. with positive common difference, is :
Mathematicsprobability2020medium
In a game two players A and B take turns in throwing a pair of fair dice starting with player A and total of scores on the two dice, in each throw is noted. A wins the game if he throws total a of 6 before B throws a total of 7 and B wins the game if he throws a total of 7 before A throws a total of six. The game stops as soon as either of the players wins. The probability of A winning the game is :
Mathematicsprobability2020medium
The probability that a randomly chosen 5-digit
number is made from exactly two digits is :
Mathematicsprobability2020medium
A dice is thrown two times and the sum of the
scores appearing on the die is observed to be
a multiple of 4. Then the conditional probability
that the score 4 has appeared atleast once is :