Recent questions tagged tifrmaths2023

2 2 votes
1 1 answer
903
903 views
Answer whether the following statements are True or False.Let $\alpha$ be a positive real number, and let $f:(0,1) \rightarrow \mathbb{R}$ be a function such that $|f(x)-...
2 2 votes
1 1 answer
639
639 views
Answer whether the following statements are True or False.Suppose $f, g: \mathbb{R} \rightarrow \mathbb{R}$ are continuous functions such that $f^{2}+g^{2}$ is uniformly ...
2 2 votes
0 0 answers
448
448 views
Answer whether the following statements are True or False.Let $\left\{f_{n}\right\}_{n}$ be a sequence of (not necessarily continuous) functions from $[0,1]$ to $\mathbb{...
3 3 votes
2 2 answers
626
626 views
Answer whether the following statements are True or False.Let $A, B \in \mathrm{M}_{2}(\mathbb{Z} / 2 \mathbb{Z})$ be such that $\operatorname{tr}(A)=\operatorname{tr}(B)...
3 3 votes
2 2 answers
602
602 views
Answer whether the following statements are True or False.Let $v_{1}, v_{2}, w_{1}, w_{2}$ be nonzero vectors in $\mathbb{R}^{2}$. Then there exists a $2 \times 2$ real m...
2 2 votes
1 1 answer
502
502 views
Answer whether the following statements are True or False.Let $A=\left(a_{i j}\right) \in \mathrm{M}_{n}(\mathbb{R})$ be such that $a_{i j} \geq 0$ for all $1 \leq i, j \...
2 2 votes
0 0 answers
396
396 views
Answer whether the following statements are True or False.Given any monic polynomial $f(x) \in \mathbb{R}[x]$ of degree $n,$ there exists a matrix $A \in \mathrm{M}_{n}(\...
2 2 votes
1 1 answer
527
527 views
Answer whether the following statements are True or False.If $A \in \mathrm{M}_{4}(\mathbb{Q})$ is such that its characteristic polynomial equals $x^{4}+1,$ then $A$ is d...
2 2 votes
0 0 answers
404
404 views
Answer whether the following statements are True or False.If $A \in \mathrm{M}_{n}(\mathbb{R})$ is such that $A B=B A$ for all invertible matrices $B \in \mathrm{M}_{n}(\...
2 2 votes
0 0 answers
340
340 views
Answer whether the following statements are True or False.There exists a homeomorphism $f: \mathbb{R} \rightarrow \mathbb{R}$ such that $f(2 x)=3 f(x)$ for all $x \in \ma...
2 2 votes
0 0 answers
369
369 views
Answer whether the following statements are True or False.There exists a continuous bijection from $[0,1] \times[0,1]$ to $\left\{(x, y) \in \mathbb{R}^{2} \mid x^{2}+y^{...
2 2 votes
0 0 answers
392
392 views
Answer whether the following statements are True or False.Let $f \in \mathbb{C}\left[z_{1}, \ldots, z_{n}\right]$ be a nonzero polynomial $(n \geq 1),$ and let\[X=\left\{...
2 2 votes
0 0 answers
473
473 views
Answer whether the following statements are True or False.A connected metric space with at least two points is uncountable.
2 2 votes
0 0 answers
317
317 views
Answer whether the following statements are True or False.If $A$ and $B$ are disjoint subsets of a metric space $(X, d),$ then\[\inf \{d(x, y) \mid x \in A, y \in B\} \ne...
2 2 votes
0 0 answers
379
379 views
Answer whether the following statements are True or False.A countably infinite complete metric space has infinitely many isolated points $($an element $x$ of a metric spa...
3 3 votes
0 0 answers
498
498 views
Answer whether the following statements are True or False.Suppose $G$ and $H$ are two countably infinite abelian groups such that every nontrivial element of $G \times H$...
2 2 votes
1 1 answer
407
407 views
Answer whether the following statements are True or False.There exists a nonabelian group $G$ of order $26$ such that every proper subgroup of $G$ is abelian.
3 3 votes
0 0 answers
495
495 views
Answer whether the following statements are True or False.Let $G$ be a group generated by two elements $x$ and $y,$ each of order $2$. Then $G$ is finite.
2 2 votes
0 0 answers
369
369 views
Answer whether the following statements are True or False.$\mathbb{R}[x] /\left(x^{4}+x^{2}+2023\right)$ is an integral domain.
2 2 votes
0 0 answers
520
520 views
Answer whether the following statements are True or False.Every finite group is isomorphic to a subgroup of a finite group generated by two elements.
2 2 votes
0 0 answers
490
490 views
Define $f: \mathbb{R} \rightarrow \mathbb{R}$ by $f(x)=\left(3 x^{2}+1\right) /\left(x^{2}+3\right)$. Let $f^{\circ 1}=f$, and let $f^{\circ n}=f^{\circ(n-1)} \circ f$ fo...
3 3 votes
1 1 answer
438
438 views
Consider the following properties of a sequence $\left\{a_{n}\right\}_{n}$ of real numbers.$\text{(I)}\displaystyle{} \lim _{n \rightarrow \infty} a_{n}=0$.$\text{(II)}$ ...
2 2 votes
0 0 answers
327
327 views
Consider sequences $\left\{x_{n}\right\}_{n}$ of real numbers such that\[\lim _{n \rightarrow \infty}\left(x_{2 n-1}+x_{2 n}\right)=2 \quad \text { and } \quad \lim _{n \...
2 2 votes
0 0 answers
360
360 views
Consider the function $f:(0, \infty) \rightarrow(0, \infty)$ given by $f(x)=x e^{x}$. Let $L:(0, \infty) \rightarrow(0, \infty)$ be its inverse function. Which of the fol...
2 2 votes
0 0 answers
383
383 views
Let $\left\{b_{n}\right\}_{n}$ be a monotonically increasing sequence of positive real numbers such that $\displaystyle{}\lim _{n \rightarrow \infty} b_{n}=$ $\infty$. Wh...
2 2 votes
0 0 answers
363
363 views
For every positive integer $n,$ define $f_{n}:[0,1] \rightarrow \mathbb{R}$ by $f_{n}(x)=\dfrac{\sin \left(n^{2} x\right)+\cos \left(e^{n} x\right)}{1+n^{2} x^{2}}$. Then...
2 2 votes
1 1 answer
448
448 views
Consider the functions $f_{1}, f_{2}:(0, \infty) \rightarrow \mathbb{R}$ defined by\[f_{1}(x)=\sqrt{x}, \quad \text { and } \quad f_{2}(x)=\sqrt{x} \sin x .\]Which of the...
2 2 votes
0 0 answers
378
378 views
Let $x_{1} \in \mathbb{R}^{2} \backslash\{0\}$ be fixed, and inductively define $x_{n+1}=A x_{n}$ for $n \geq 1,$ where $A$ is the $2 \times 2$ real matrix given by\[A:=\...
2 2 votes
1 1 answer
372
372 views
Let $T: \mathrm{M}_{3}(\mathbb{R}) \rightarrow \mathbb{R}^{3}$ be the linear map defined by $T(A)=A\left(\begin{array}{c}1 \\ 0 \\ -1\end{array}\right)$. Then the dimensi...
3 3 votes
0 0 answers
392
392 views
Let $V=\{f(x) \in \mathbb{R}[x] \mid f(0)=0\},$ viewed as a real vector space. Consider the following assertions:$\text{(I)}$ $V$ contains three linearly independent poly...