Nothing Special   »   [go: up one dir, main page]

Bachelor of Science (B.SC.) Semester-I Examination Mathematics (Algebra and Trigonometry) Optional Paper-1

Download as pdf or txt
Download as pdf or txt
You are on page 1of 3

NIR/KW/18/2008

Bachelor of Science (B.Sc.) Semester—I Examination

MATHEMATICS (ALGEBRA AND TRIGONOMETRY)


Optional Paper—1

Time : Three Hours] [Maximum Marks : 60

N.B. :— (1) Solve all the five questions.


(2) All questions carry equal marks.

(3) Question Nos. 1 to 4 have an alternative, solve each question in full or its alternative
in full.
UNIT—I
1. (A) Find non-singular matrices P and Q such that PAQ is in the normal form. Also find rank
of A where :

1 1 1 
1 − 1 − 1
A=   6
3 1 1 

(B) Find the value of λ, so that following equations :


x – y + z = 1, x + 2y + 4z = λ, 2x + 4y + 8z = λ 2
may have solution and solve them completely in each case. 6
OR
(C) Find eigen values of the matrix :

3 1 4
0 2 6
 
0 0 5

and eigen vectors corresponding to the greatest eigen value of the matrix. 6

 0 0 1
 3 1 0
(D) Verify Cayley-Hamilton theorem for the matrix A =   6
− 2 1 4

UNIT—II
2. (A) Solve the equation
x4 – 2x3 – 17x2 + 18x + 72 = 0,
given that sum of the two roots being equal to the sum of the other two. 6

BKR—11055 1 (Contd.)
(B) Find the condition that the roots of the equation x3 + ax2 – bx + c = 0 are in arithmetic
progression. Hence solve the equation x3 – 9x2 + 23x – 15x = 0. 6
OR
(C) Solve x3 – 27x + 54 = 0 by Cardon’s method. 6
(D) Solve the reciprocal equation 2x4 – 5x3 + 4x2 – 5x + 2 = 0. 6
UNIT—III
3. (A) Solve the equation
x5 – x3 + x2 – 1 = 0
using DeMoivre’s theorem. 6
(B) Prove that :

 nπ 
(i) (1+ i 3 ) n
(
+ 1− i 3 ) n
= 2n+1 . cos  
 3 
(ii) Separate sinh (α – iβ ) into real and imaginary parts. 6
OR
(C) If sin (θ + iφ) = cos α + i sin α ,
Prove that :
(i) cos2 θ = ± sin α
(ii) sinh2 φ = ± sin α . 6
(D) Prove that :

 a + ib  b
(i) log   = 2 i tan–1  
 a − ib  a 

π  1 1 1  1 1  1  1 1 
(ii) =  +  −  +  +  +  − ....... 6
4  2 3  3  23 33  5  25 35 

UNIT—IV
4. (A) Prove that the set G = {0, 1, 2, 3, 4, 5, 6} is a finite abelian group of order 7 with respect
to addition modulo 7. 6
(B) Prove that a necessary and sufficient condition for a non-empty subset H of a group (G, o )
to be a subgroup is that

a, b ∈ H ⇒ a o b−1 ∈ H 6

OR
(C) Prove that intersection of two subgroups of a group G is a subgroup of G. Give an example
to prove that union of two subgroups of G is not necessarily a subgroup of G. 6
(D) Show that the four permutations I = (a), (a b), (c d), (a b) . (c d) on four symbols
a, b, c, d form a finite abelian group with respect to the multiplication of permutations.
6
BKR—11055 2 NIR/KW/18/2008
Question—V
5 0 5
0 2 0
5. (A) Find the sum and product of eigen values of the matrix  . 1½
4 0 3

(B) Find K, if the system of equations x + 4y + 2z = 0, 4x + 9y + z = 0, Kx + 3y + Kz = 0


has non-trivial solution. 1½
(C) Use Descartes’s rule of signs to discuss about real roots (positive and negative) and imaginary
roots of the equation x4 + 2x3 – 16x2 – 22x + 7 = 0. 1½
(D) If α, β and γ are the roots of the equation x3 + 9x2 – 7x + 5 = 0, find Σα 2 . 1½
(E) Find general value of Log (–7 i). 1½
(F) Prove that :
cos (ix) = cosh x and
sin (ix) = i sinh x. 1½
(G) Verify whether the set of integers I with binary operation ‘o ’ defined by a o b = a − b ∀ a , b ∈ I
is a group. 1½

1 2 3   1 2 3
(H) If A = 1 3 2  and B =  2 1 3 , find AB and BA. 1½
   

BKR—11055 3 NIR/KW/18/2008

You might also like