Electronics Engineering (Semester 4)
TOTAL MARKS: 80
TOTAL TIME: 3 HOURS
(1) Question 1 is compulsory.
(2) Attempt any three from the remaining questions.
(3) Assume data if required.
(4) Figures to the right indicate full marks.
1 (a) "A random variable X has the probability function:
X: |
-2 |
-1 |
0 |
1 |
2 |
3 |
P (X = x): |
0.1 |
k |
0.2 |
2k |
0.3 |
3k |
Find: (i) k (ii) P(x ≤ 1) (iii) P(-2 < x < 1) (iv) Obtain the distribution function of X
"
(5 marks)
1 (b) In the set of natural numbers, prove that the relation xRy if and only if x2 - 4xy + 3y2=0, is reflexive, but neither symmetric nor transitive.(5 marks)
1 (c) Find the characteristic roots of A30-9A28 where
(5 marks)
1 (d) Find Laurent's series about z = -2 for:
(5 marks)
2 (a) If X, Y are independent Poisson variates such that P(X=1) = P(X=2) and P(Y=2) = P(Y=3) find the variance of 2X - 3Y.(7 marks)
2 (b) Find the Residues of
<bt> at its poles.</bt>(7 marks)
2 (c) If
find cosA.(6 marks)
3 (a) Check whether A = {2, 4, 12, 16} and B = {3, 4, 12, 24} are lattices under divisibility? Draw their Hasse diagrams.(7 marks)
3 (b) Nine items of a sample had the following values.
45, 47, 50, 52, 48, 47, 49, 53, 51.
Does the mean of 9 items differ significantly from the assumed population mean 47.5 ?(7 marks)
3 (c) Find characteristic equation of the matrix A and hence find matrix represented by A8-5A7+7A6-3A5+A4-5A3+8A2-2A1+I where:
(6 marks)
4 (a) The average of marks scored by 32 boys is 72 with standard deviation 8 while that of 36 girls is 70 with standard deviaiton 6. Test at 1% level of significance whether the boys perform better than the girls.(7 marks)
4 (b) Let
and + and · be the matrix addition and matrix multiplication. Is ( S, +, · ) an integral domain? Is it a field?
(7 marks)
4 (c) Show that ∫c dz/(z+1) = 2πI, where C is the circle |z| = 2. Hence deduce that:
(6 marks)
5 (a) The number of defects in printed circuit board is hypothesised to follow Poisson distribution. A random sample of 60 printed boards showed the following data.
Number of Defects: | 0 | 1 | 2 | 3 |
Observed Frequency: | 32 | 15 | 9 | 4 |
(7 marks)
5 (b) "If f and g are defined as
f: R → R, f(x) = 2x - 3
g: R → R, g(x) = 4 - 3x
i) Verify that (fog)-1 = g-1 of-1
ii) Solve fog(x) = g of(1)"
(7 marks)
5 (c) For a distribution the mean is 10, variance is 16, γ1 is 1 and β2 is 4. Find the first four moments about the origin. Comment on the nature of this distribution.
(6 marks)
6 (a) Prove that the set A={0, 1, 2, 3, 4, 5} is a finite abelian group under addition modulo 6.(7 marks)
6 (b) If
where C is the circle x2 + y2 = 4. Find the values of
(i) f(3) (ii) f'(1-i) (iii) f"(1-i)(7 marks)
6 (c) A manufacturer known from his experience that the resistance of resistors he produces is normal with µ = 100Ω and standard deviation σ=2Ω. What percentage of resistors will have resistance between 98Ω and 102Ω?
(6 marks)
7 (a) By using residue theorem evaluate
where C is |z|=1(7 marks)
7 (b) The ratio of the probability of 3 successes in 5 independent trials to the pobability of 2 successes in 5 independent trials is 1/4. What is the probability of 4 successes in 6 independent trials?(7 marks)
7 (c) Prove that both A and B are not diagonalisable but AB is diagonalisable.
(6 marks)