Recent questions in Others

0 votes
1 answer
1543
Which of the following are true?$\frac {2019}{2020} < \frac {2020}{2021}$$x+\frac{1}{x} \geq 2$ for all $x>0$$2^{60} >5^{24}$$2^{314} <31^{42}$
0 votes
1 answer
1544
0 votes
2 answers
1545
The sum and product of the roots of the polynomial $9x^2+171x-81$ are, respectively:$-19$ and $-9$$19$ and $9$$-9$ and $19$$9$ and $-19$
0 votes
1 answer
1547
Which of the following inequalities are true?$e^x\geq(1+x)$ for $x\geq 0$$e^x\leq(1+x)$ for $x<0$$\text{In}(x)<(1+x)$ for $x>0$$e^x<x^2$ for all real numbers $x$
1 votes
1 answer
1548
A permutation $\sigma$ is a bijection from the set $[n]=\{1,2,\dots ,n\}$ to itself. We denote it using the notation$$\begin{pmatrix}1 & 2 & … & n \\ {\sigma(1)} & {\si...
0 votes
1 answer
1556
Let $R$ be the set of all binary relations on the set $\{1,2,3\}$. Suppose a relation is chosen from $R$ at random. What is the probability that the chosen relation is sy...
0 votes
1 answer
1558
For the function $f(x)=\text{ln}(x)/x$, show that the maximum value of $f(x)$ occurs when $x=e$. Use this to show that $x^e<e^x$ for all positive values of $x$.
0 votes
1 answer
1559
Given the set of letters $\text{\{a,b,c,d,e,f,g,h,i,j,k,l,m\}},$ we can list out all permutations of these letters in lexicographic (dictionary) order. The first three pe...