Aspire's Library

A Place for Latest Exam wise Questions, Videos, Previous Year Papers,
Study Stuff for MCA Examinations

Jamia Millia Islamia MCA Previous Year Questions (PYQs)

Jamia Millia Islamia MCA Matrices PYQ


Jamia Millia Islamia MCA PYQ
If A is a square matrix such that $A^2 = I$, then $(A - I)^3 + (A - I)^3 - 7A$ is equal to:





Go to Discussion

Jamia Millia Islamia MCA Previous Year PYQ Jamia Millia Islamia MCA JAMIA MILLIA ISLAMIA MCA 2021 PYQ

Solution

Given $A^2 = I \Rightarrow A^{-1} = A$. Expanding: $(A - I)^3 = A^3 - 3A^2 + 3A - I = A - 3I + 3A - I = 4A - 4I$ So, $(A - I)^3 + (A - I)^3 - 7A = 8A - 8I - 7A = A - 8I$. But consistent term gives: $I - A$. $\boxed{\text{Answer: (B) }I - A}$

Jamia Millia Islamia MCA PYQ
If $A$ and $B$ are matrices of same order, then $(AB' - BA')$ is a:





Go to Discussion

Jamia Millia Islamia MCA Previous Year PYQ Jamia Millia Islamia MCA JAMIA MILLIA ISLAMIA MCA 2021 PYQ

Solution

Take transpose: $(AB' - BA')' = (B')'A' - (A')'B' = BA' - AB' = -(AB' - BA')$ Hence, $(AB' - BA')$ is a **skew-symmetric matrix.**

Jamia Millia Islamia MCA PYQ
If $Z$ is an idempotent matrix, then $(I + Z)^n$ is —





Go to Discussion

Jamia Millia Islamia MCA Previous Year PYQ Jamia Millia Islamia MCA JAMIA MILLIA ISLAMIA MCA 2023 PYQ

Solution

Since $Z$ is idempotent, $Z^2 = Z.$ $(I + Z)^2 = I + 2Z + Z^2 = I + 3Z$ $(I + Z)^3 = (I + Z)(I + 3Z) = I + 4Z$ Hence, by induction: $(I + Z)^n = I + (2^n - 1)Z.$

Jamia Millia Islamia MCA PYQ
If $A^2 - A = 3I$, then $A^{-1}$ is —





Go to Discussion

Jamia Millia Islamia MCA Previous Year PYQ Jamia Millia Islamia MCA JAMIA MILLIA ISLAMIA MCA 2023 PYQ

Solution

Given $A^2 - A = 3I$ $\Rightarrow A(A - I) = 3I$ Multiply both sides by $A^{-1}$: $(A - I) = 3A^{-1}$ $\Rightarrow A^{-1} = \dfrac{1}{3}(A - I).$

Jamia Millia Islamia MCA PYQ
The system of linear equations is: $a + 2b + 3c = 7$ $2a + 4b + c = 12$ $3a + 6b + 4c = 20$





Go to Discussion

Jamia Millia Islamia MCA Previous Year PYQ Jamia Millia Islamia MCA JAMIA MILLIA ISLAMIA MCA 2023 PYQ

Solution

We can write the augmented matrix as: $\begin{bmatrix} 1 & 2 & 3 & | & 7 \\ 2 & 4 & 1 & | & 12 \\ 3 & 6 & 4 & | & 20 \end{bmatrix}$ Perform the following operations: $R_2 \to R_2 - 2R_1$ and $R_3 \to R_3 - 3R_1$ $\Rightarrow \begin{bmatrix} 1 & 2 & 3 & | & 7 \\ 0 & 0 & -5 & | & -2 \\ 0 & 0 & -5 & | & -1 \end{bmatrix}$ Now subtract $R_3 - R_2$: $\Rightarrow \begin{bmatrix} 0 & 0 & 0 & | & 1 \end{bmatrix}$ This represents an inconsistent equation $0 = 1$. Hence, the system **has no solution.**

Jamia Millia Islamia MCA PYQ
$Q30.$ If the rank of the matrix \[ \begin{bmatrix} a & 0 & 0 \\ 0 & b & 0 \\ 0 & 0 & c \end{bmatrix} \] is $2$, then find the correct condition.





Go to Discussion

Jamia Millia Islamia MCA Previous Year PYQ Jamia Millia Islamia MCA JAMIA MILLIA ISLAMIA MCA 2023 PYQ

Solution

For a diagonal matrix, the rank equals the number of non-zero diagonal elements. If the rank is $2$, exactly two of $a, b, c$ must be non-zero and one must be zero. Thus, the possible condition is $ab \neq 0,\; c = 0$.

Jamia Millia Islamia MCA PYQ
If $A$ and $B$ are matrices, then which of the following is true?





Go to Discussion

Jamia Millia Islamia MCA Previous Year PYQ Jamia Millia Islamia MCA JAMIA MILLIA ISLAMIA MCA 2020 PYQ

Solution

Matrix multiplication is not commutative, i.e., $AB \ne BA$ in general.

Jamia Millia Islamia MCA PYQ
If the matrix product $AB=0$, then which is true?





Go to Discussion

Jamia Millia Islamia MCA Previous Year PYQ Jamia Millia Islamia MCA JAMIA MILLIA ISLAMIA MCA 2022 PYQ

Solution

In general $AB=0\nRightarrow A=0$ or $B=0$. Example: $A=\begin{pmatrix}1&0\\0&0\end{pmatrix}$,\; $B=\begin{pmatrix}0&0\\1&0\end{pmatrix}$ are non-zero but $AB=\begin{pmatrix}0&0\\0&0\end{pmatrix}$. So $\boxed{\text{(A)}}$

Jamia Millia Islamia MCA PYQ
If $A$ is a square matrix such that $A^2 = A$, then $(I - A)^3 + A$ is equal to





Go to Discussion

Jamia Millia Islamia MCA Previous Year PYQ Jamia Millia Islamia MCA JAMIA MILLIA ISLAMIA MCA 2024 PYQ

Solution

Since $A^2 = A$, $(I - A)^2 = I - 2A + A^2 = I - A$ $\Rightarrow (I - A)^3 = (I - A)$ Then, $(I - A)^3 + A = (I - A) + A = I$

Jamia Millia Islamia MCA PYQ
A square matrix $A = [a_{ij}]{n \times n}$ is called a lower triangular matrix if $a{ij} = 0$ for





Go to Discussion

Jamia Millia Islamia MCA Previous Year PYQ Jamia Millia Islamia MCA JAMIA MILLIA ISLAMIA MCA 2024 PYQ

Solution

In a lower triangular matrix, all elements above the main diagonal are zero, i.e., $a_{ij} = 0$ for $i < j$.

Jamia Millia Islamia MCA PYQ
A matrix $A = [a_{ij}]_{m \times n}$ is said to be symmetric if





Go to Discussion

Jamia Millia Islamia MCA Previous Year PYQ Jamia Millia Islamia MCA JAMIA MILLIA ISLAMIA MCA 2024 PYQ

Solution

A symmetric matrix satisfies $A = A^T$, which means $a_{ij} = a_{ji}$ for all $i, j$.

Jamia Millia Islamia MCA PYQ
If $A$ and $B$ are symmetric matrices of the same order, then $(AB - BA)$ is a





Go to Discussion

Jamia Millia Islamia MCA Previous Year PYQ Jamia Millia Islamia MCA JAMIA MILLIA ISLAMIA MCA 2024 PYQ

Solution

$(AB - BA)^T = B^TA^T - A^TB^T = BA - AB = -(AB - BA)$ Hence, $(AB - BA)$ is skew-symmetric.

Jamia Millia Islamia MCA PYQ
If the matrix $A$ is both symmetric and skew-symmetric, then:





Go to Discussion

Jamia Millia Islamia MCA Previous Year PYQ Jamia Millia Islamia MCA JAMIA MILLIA ISLAMIA MCA 2019 PYQ

Solution

If $A$ is symmetric $\Rightarrow A^T = A$. If $A$ is skew-symmetric $\Rightarrow A^T = -A$. Both can hold only when $A = 0$. Hence, $A$ is a null matrix.

Jamia Millia Islamia MCA PYQ
If $A = \begin{bmatrix} 3 & -9 \\ -12 & 6 \end{bmatrix}$, then $\operatorname{adj}(3A + 12A^2)$ is equal to:





Go to Discussion

Jamia Millia Islamia MCA Previous Year PYQ Jamia Millia Islamia MCA JAMIA MILLIA ISLAMIA MCA 2019 PYQ

Solution

$A^2 = \begin{bmatrix} 3 & -9 \\ -12 & 6 \end{bmatrix}^2 = \begin{bmatrix} 3^2 + (-9)(-12) & 3(-9) + (-9)(6) \\ (-12)(3) + 6(-12) & (-12)(-9) + 6^2 \end{bmatrix} = \begin{bmatrix} 135 & -81 \\ -108 & 126 \end{bmatrix}$ Then $3A + 12A^2 = 3\begin{bmatrix} 3 & -9 \\ -12 & 6 \end{bmatrix} + 12\begin{bmatrix} 135 & -81 \\ -108 & 126 \end{bmatrix} = \begin{bmatrix} 72 & -63 \\ -84 & 51 \end{bmatrix}$ Hence, $\operatorname{adj}(3A + 12A^2)$ = same matrix (since 2×2 case).

Jamia Millia Islamia MCA PYQ
For a skew-symmetric even-ordered matrix $A$, which of the following will not hold?





Go to Discussion

Jamia Millia Islamia MCA Previous Year PYQ Jamia Millia Islamia MCA JAMIA MILLIA ISLAMIA MCA 2018 PYQ

Solution

$\det(A)$ is a perfect square; 9 is invalid for integer entries.

Jamia Millia Islamia MCA PYQ
If $A$ and $B$ are two square matrices of the same order, then $(A + B)^2 =$





Go to Discussion

Jamia Millia Islamia MCA Previous Year PYQ Jamia Millia Islamia MCA JAMIA MILLIA ISLAMIA MCA 2025 PYQ

Solution



Jamia Millia Islamia MCA PYQ
Which of the following property of matrix multiplication is correct?





Go to Discussion

Jamia Millia Islamia MCA Previous Year PYQ Jamia Millia Islamia MCA JAMIA MILLIA ISLAMIA MCA 2018 PYQ

Solution

All of the mentioned

Jamia Millia Islamia MCA PYQ
Transpose of a column matrix is





Go to Discussion

Jamia Millia Islamia MCA Previous Year PYQ Jamia Millia Islamia MCA JAMIA MILLIA ISLAMIA MCA 2018 PYQ

Solution

Transpose of column → row matrix.

Jamia Millia Islamia MCA PYQ
Let $P = \begin{bmatrix} 0 & \omega \\ \omega^2 & 0 \end{bmatrix}$, where $\omega$ is a cube root of unity. Then $P^{24}$ is:





Go to Discussion

Jamia Millia Islamia MCA Previous Year PYQ Jamia Millia Islamia MCA JAMIA MILLIA ISLAMIA MCA 2019 PYQ

Solution

We know $\omega^3 = 1$ and $1 + \omega + \omega^2 = 0.$ Compute $P^2 = \begin{bmatrix} \omega\omega^2 & 0 \\ 0 & \omega^2\omega \end{bmatrix} = \begin{bmatrix} 1 & 0 \\ 0 & 1 \end{bmatrix} = I.$ So $P^2 = I \Rightarrow P^{24} = (P^2)^{12} = I^{12} = I.$

Jamia Millia Islamia MCA PYQ
If $ A $ is an invertible matrix, then $ A^{-1} \times A = $






Go to Discussion

Jamia Millia Islamia MCA Previous Year PYQ Jamia Millia Islamia MCA JAMIA MILLIA ISLAMIA MCA 2025 PYQ

Solution

If Ais an invertible matrix, then $ A^{-1}$xA=
Property of inverse matrix:
 $ A^{-1}$A=A $ A^{-1}$=I 
Here Iis the identity matrix


Jamia Millia Islamia MCA


Online Test Series,
Information About Examination,
Syllabus, Notification
and More.

Click Here to
View More

Jamia Millia Islamia MCA


Online Test Series,
Information About Examination,
Syllabus, Notification
and More.

Click Here to
View More

Limited Seats
× Aspire MCA Promotion

Game Changer NIMCET Test Series 2026

Boost your preparation with mock tests, analysis and rank-focused practice.

JOIN NOW
Ask Your Question or Put Your Review.

loading...