All Exams  >   Civil Engineering (CE)  >   RRB JE for Civil Engineering  >   All Questions

All questions of Engineering Mathematics for Civil Engineering (CE) Exam

The number of linearly independent eigenvectors of 
  • a)
    0    
  • b)
    1    
  • c)
    2    
  • d)
    Infinit e 
Correct answer is 'B'. Can you explain this answer?

Pranjal Sen answered
Number of linear independent vectors is equal to the sum of Geometric Multiplicity of eigen values. Here only eigen value is 2. To find Geometric multiplicity find n-r of (matrix-2I), where n is order and r is rank. Rank of obtained matrix is 1 and n=2 so n-r=1. Therefore the no of linearly independent eigen vectors is 1

The eigenvalues of
  • a)
    -19,5,37
  • b)
    19,-5,-37
  • c)
    2,-3,7
  • d)
    3,-5,37
Correct answer is option 'A'. Can you explain this answer?

Avinash Sharma answered
The eigenvalues of an upper triangular matrix are simply the diagonal entries of the matrix.
Hence 5, -19, and 37 are the eigenvalues of the matrix. Alternately, look atd
λ = 5, -19, 37

A fair coin is tossed 10 times. What is the probability that ONLY the first two tosses will yield heads? 
  • a)
  • b)
  • c)
  • d)
Correct answer is option 'C'. Can you explain this answer?

Rhea Reddy answered
Let A be the event that first toss is head  
And B be the event that second toss is head. 
By the given condition rest all 8 tosses should be tail
∴ The probability of getting head in first two cases 

Eigen values of a matrix    are 5 and 1. What are the eigen values of the matrix S2  = SS?
  • a)
    1 and 25  
  • b)
    6 and 4  
  • c)
    5 and 1  
  • d)
    2 and 10 
Correct answer is option 'A'. Can you explain this answer?

EduRev GATE answered
We know If λ be the eigen value of A ⇒λ2 is an eigen value of A2 .
For S matrix, if eigen values are λ1, λ2, λ3,... then for S² matrix, the eigen values will be λ²1 λ²2 λ²3......
For S matrix, if eigen values are 1 and 5 then for S² matrix, the eigen values are 1 and 25

  • a)
    ∞    
  • b)
    2    
  • c)
    0
  • d)
    1
Correct answer is option 'C'. Can you explain this answer?

Yash Patel answered
the squeeze theorem for this. Recall that sinx is only defined on −1≤sinx≤1. Therefore

In an M × N matrix such that all non-zero entries are covered in a rows and b column. Then the maximum number of non-zero entries, such that no two are on the same row or column, is 
  • a)
    ≤ a + b    
  • b)
    ≤ max (a, b)  
  • c)
    ≤ min[ M –a, N–b]    
  • d)
    ≤ min  {a, b} 
Correct answer is option 'D'. Can you explain this answer?

Naroj Boda answered
Suppose a < b, for example let a = 3, b= 5, then we can put non-zero entries only in 3 rows and 5 columns. So suppose we put non-zero entries in any 3 rows in 3 different columns. Now we can’t put any other non-zero entry anywhere in matrix, because if we put it in some other row, then we will have 4 rows containing non-zeros, if we put it in one of those 3 rows, then we will have more than one non-zero entry in one row, which is not allowed.
So we can fill only “a” non-zero entries if a < b, similarly if b < a, we can put only “b” non-zero entries. So answer is ≤min(a,b), because whatever is less between a and b, we can put atmost that many non-zero entries.

If the rank of a (5×6) matrix Q is 4, then which one of the following statements is correct?  
  • a)
    Q will have four linearly independent rows and four linearly independent columns  
  • b)
    Q will have four lineally independent rows and five lineally independent columns
  • c)
    QQT will be invertible
  • d)
    QTQ will be invertible 
Correct answer is option 'A'. Can you explain this answer?

Given that rank Q is 4, so it will have 4 linearly independent columns as well as 4 linearly independent rows (∵ row rank of a matrix = column rank of a matrix)

So, A is correct and accordingly B is false.

C is false as order of QQ^T will be 5 x 5 and given that rank of Q is 4 i.e. < 5. So the matrix is QQ^T will be singular and hence not invertible.

Similarly D is false as order of Q^T Q will be 6 x 6 and the matrix is Q^T Q will be singular and hence not invertible.

Consider the following two statements about the function f(x) = |x|  
P: f(x) is continuous for all real values of x
 Q: f(x) is differentiable for all real values of x  
Which of the f oll owi ng is TRU E? 
  • a)
    P is true and Q is false  
  • b)
    P is false and Q is true  
  • c)
    Both P and Q are true  
  • d)
    Both P and Q are false  
Correct answer is option 'A'. Can you explain this answer?

Avinash Sharma answered
The graph of f(x) is  
f(x) is continuous for all real values of x   Lim |x| = Lim |x| = 0 
as can be seen from graph of |x|. 
and  Lim f(x) = +1 as can be seen from graph of |x| 
 x → 0+ 
Left deriva tive ≠ Rig ht derivative 
So |x| is continuous but not differentiable at x = 0. 

The minimum point of the function f(x) = (x2/3) – x is at 
  • a)
     x = 1 
  • b)
    x = -1
  • c)
     x = 0 
  • d)
    x = 1/√3
Correct answer is option 'A'. Can you explain this answer?

Avinash Sharma answered
Correct Answer :- a
Explanation : f(x) = (x^2/3) - x
f'(x) = 2/3(x-1/2) - 1
f"(x) = -1/3(x-3/2)
For critical points. f′(x)=0
=> 2/3(x-1/2) - 1 = 0 
f has minimum value of x = 1

The general solution of (x2 D2 – xD), y= 0 is :
  • a)
     y = C1 + Cex
  • b)
     y = C1 + Cx 
  • c)
    y = C1 x + Cx2
  • d)
    y = C1 + Cx
Correct answer is option 'C'. Can you explain this answer?

Akshara Rane answered
+ 4xD + 3y = 0) can be found by assuming a solution of the form y = e^(mx).

Substituting this into the differential equation gives:

x^2(m^2)e^(mx) + 4xme^(mx) + 3e^(mx) = 0

Dividing through by e^(mx) gives:

m^2x^2 + 4mx + 3 = 0

This is a quadratic equation in m, which can be solved using the quadratic formula:

m = (-4x ± √(16x^2 - 4(3)(x^2))) / (2x^2)

Simplifying this gives:

m = (-2 ± √1) / x

m1 = -1/x, m2 = -3/x

Therefore, the general solution is a linear combination of the two solutions:

y = c1e^(-x) + c2e^(-3x)

where c1 and c2 are arbitrary constants determined by initial or boundary conditions.

Find the Eigenvalues of matrix
  • a)
    8, 2
  • b)
    3, -3 
  • c)
    -3, -5 
  • d)
    5, 0
Correct answer is option 'A'. Can you explain this answer?

Sanya Agarwal answered
A - λI = 0
Now, After taking the determinant:
(4 - λ)2 - 1 = 0
16 + λ2 - 8λ - 1 = 0
λ2 - 8λ + 15 = 0
 - 3) (
λ
 - 5) = 0
λ
 = 3, 5

Chapter doubts & questions for Engineering Mathematics - RRB JE for Civil Engineering 2025 is part of Civil Engineering (CE) exam preparation. The chapters have been prepared according to the Civil Engineering (CE) exam syllabus. The Chapter doubts & questions, notes, tests & MCQs are made for Civil Engineering (CE) 2025 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests here.

Chapter doubts & questions of Engineering Mathematics - RRB JE for Civil Engineering in English & Hindi are available as part of Civil Engineering (CE) exam. Download more important topics, notes, lectures and mock test series for Civil Engineering (CE) Exam by signing up for free.

Signup to see your scores go up within 7 days!

Study with 1000+ FREE Docs, Videos & Tests
10M+ students study on EduRev