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Objective Type Questions
10×15=15
Total No. of Questions : 11
Total No. of Printed Pages : 13
1. Chose the correct answers.
IJ-442
M.A./M.Sc. Ist Semester (Reg./Pvt./ATKT)
Examination, 2022-23
Mathematics
Paper - II
Real Analysis
Time : 3 Hours
[Maximum Marks : Reg. 85
Pvt. 100]
Note:- All questions are compulsory.
SECTION - 'A'
(i)
The partition p' is a refinement of P if:
- P' ⊃ P
- P' = P
- P' < P
- P' ⊃ P
(ii)
∫fda is given by:
- Sup L(p,f,α)p∈[a,b]
- inf U(p,f,α)p∈[a,b]
- ∑n=1∞MΔα
- ∑n=1∞mΔα
(iii)
Let f∈R(α) on [a,b], m ≤ f ≤ M, φ be continuous [m, M] and h(x) = φ(f(x)) on [a,b]. Then-
- |f| ∈ R(α)
- h ∈ R(α)
- φ = R
- None of these
(iv)
In rectifiable curve Λ(p) is given by-
- ∑i=1n|Δxi|
- ∑i=1n|Δxi|-4(xi-1)
- ∑i=1n|Δxi|-4(xi-1)|
- ∑i=1n|Δxi|+4(xi-1)|
(v)
If the set of numbers Λ(p) is unbounded then 4 is called-
- rectifiable
- vector-valued function
- non rectifiable
- None of these
(vi)
Let ∑n=1∞un be a series of real numbers then ∑n=1∞un is said to be conditional convergent if the series ∑n=1∞un converges, but :
- ∑n=1∞un oscillates
- ∑n=1∞un diverges
- ∑n=1∞un converges and diverges both
- None of these
(vii)
If a sequence is uniformly convergent then it is necessarily -
- divergent
- oscillates
- (a) & (b) both
- pointwise convergent
(viii)
If fn(x) = n2x / (1+n2x2) defined in [0, 1] then by Mn test it is-
- non-uniformly convergent
- uniformly convergent
- divergent
- None of these
(ix)
If {fn} is a sequence of continuous functions on E and if fn → f uniformly on E, then-
- f is discontinuous on E
- f is continuous on E
- f is complete metric space on E
- None of these
(x)
Every span is a-
- vector space
- dimension
- (a) & (b) both
- None of these
(xi)
||A|| is given by :
- infx∈Rn, |x|=1 |AX|
- supx∈Rn, |x|=1 |AX|
- infx∈Rn, |x|≠0 |X|
- supx∈Rn, |x|≠0 |AX|
(xii)
A contraction map is always:
- discontinuous
- continuous
- reimann integrable
- (a) & (b) both
(xiii)
Radius of convergence R of the power series ∑cnzn, where cn = nn is:
- ⅓
- 3
- c
- o
(xiv)
A mapping f of E into Rn is said to be of class CII if each component fi is of:
- Class CII
- Class CI
- Class f
- None of these
(xv)
If Ax ∈ L(Rn), Ay ∈ L(Rn) then A(h,k) is given by:
- Ax h + Ay k
- Ax h - Ay k
- -Ax h
- -Ay k
SECTION - 'B'
Short Answer Type Questions 5×5=25
2.
If P* is a refinement of p, then prove that L (p, f, α) ≤ L (p*, f, α).
OR
3.
If f ∈ R(α) and g ∈ R(α) on [a,b], then prove that :
- fg ∈ R(α)
- |f| ∈ R(α)and ∫ab|f|dα ≤ |∫abf dα|
3.
Define Integration of vector-valued functions.
OR
4.
Explain Rectifiable Curves.
4.
Explain the difference of pointwise convergence and uniform convergence.
OR
5.
Prove that the sequence of functions {fn} defined on E, converges uniformly on E if and only if for every ε > 0 there exists an integer N such that m ≥ N, n ≥ N, x ∈ E implies |fm(x) - fn(x)| ≤ ε.
5.
If A ∈ L(Rn), Rn then prove that ||A|| < ∞ and A is uniformly continuous mapping of Rn into Rn.
SECTION - 'C'
Long Answer Type Questions 5×9=45
6.
Suppose E be an open set in Rn, f maps E into Rn and x ∈ E and Limh→0 &frac{|f(x+h)-f(x)-Ah|}{|h|} = 0 holds with A=A1 and with A=Ax. Then prove that A1 = Ax.
OR
6.
Suppose f is defined in an open set E ¹ R2 and D1f and D2f exist at every point of E. Suppose Q ¹ E is a closed rectangle with sides parallel to the coordinate axes, having (a, b) and (a + h, b + k) as opposite vertices (h ≠ 0, k ≠ 0). put Δ(f,Q) = f(a + h, b + k) - f(a + h, b) - f(a, b + k) + f(a, b) Then prove that there is a point (x, y) in the interior of Q such that Δ(f, Q) = hk, D1D2f(x, y).
OR
6.
If A ∈ L(Rn, Rm) and if A1 is invertible, then there corresponds to every k ∈ Rm a unique h ∈ Rn such that A(h, k) = 0. Then prove that this h can be computed from k by the formula h = -(A1)-1 A2k.
7.
Let f be a bounded function and α be a monotonically increasing function on [a, b]. Then prove that f ∈ R (α) on [a, b] if and only if for every ε > 0 there exists a partition p such that U (p, f, α) - L (p, f, α) < ε.
OR
7.
Let f ∈ R on [a, b]. For a ≤ x ≤ b put F(x) = ∫axf(t)dt. Then prove that F is continuous on [a, b]; furthermore if f is continuous at a point x0 of [a, b], then F is differentiable at x0 and F'(x0) = f(x0).
8.
Let γ be a continuously differentiable curve on [a, b], then prove that γ is rectifiable and Λγ(a, b) = ∫ab|γ'(t)|dt.
OR
9.
Let ∑an be a given series of real number which converges but not absolutely. Suppose -∞ ≤ α ≤ β ≤ ∞ Then prove that there exists a rearrangement ∑a'n with partial sums s'n such that lim inf s'n = α, lim sup s'n = β.
9.
Suppose fn → f uniformly on a set E in a metric space. Let x be a Limit point of E, and Suppose that limt→x fn(t) = An (n=1, 2, 3, ...) Then prove that {An} converges and limn→∞ An = limt→x f(t).
OR
10.
Let α be monotonically increasing on [a, b] suppose fn ∈ R(α) on [a, b], for n=1, 2, 3, ....., and suppose fn → f uniformly on [a, b]. Then prove that f ∈ R (α) on [a, b] and ∫abfdα = limn→∞ ∫abfn dα.
10.
Suppose E is an open set in Rn, f maps E into Rm, f is differentiable at x0 ∈ E. g maps an open set containing f(E) into Rk, and g is differentiable at f(x0). Then prove that the mapping F of E into Rk defined by F(x) = g(f(x)) is differentiable at x0 and F'(x0) = g'(f(x0)) f'(x0).
OR
11.
Suppose f maps a convex open set E ¹ Rn into Rn, f is differentiable. in E and there is a real number M such that ||f'(x)|| ≤ M for every x ∈ E. Then prove that ||f(b) - f(a)|| ≤ M|b-a| ∀ a ∈ E, b ∈ E.
11.
Let ∑anxn be a power series with unit radius of convergence and let f(x) = ∑anxn. If the series ∑an converges then prove that lim f(x) = ∑an.
OR
12.
Let f be a c1-mapping of an open set E ¹ Rn into Rn, such that f(a, b) = 0 for some point (a, b) ∈ E. Put A = f1 (a, b) and
assume that A1 is invertible. Then prove that there exist open set U ¹ Rnm and W ¹ Rn with (a, b) ∈ U and b ∈ W, having the following property: To every Y ∈ W corresponds a unique x such that (x, y) = 0 and f(x,y)=0. If this x is defined to be g(y), then prove that g is a c1-mapping of W into Rn. g (b) = a, f (g (y), y) = 0 (y ∈ w).