dREaM
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 1d answered What is the probability that a psychic correctly “predicts” the outcome of at least 5 out of 10 coin flips? 1d answered Smallest $n$ such that $U(n)$ contains a subgroup isomorphic to $\mathbb Z_5 \oplus \mathbb Z_5$ 1d answered Is $S_1\cap S_2$ and $S_1\setminus S_2$ always linearly dependent if $S_1$ and $S_2$ are linearly dependent subsets of vector space $V$? 2d answered Show that $1^k+2^k+\cdots+n^k$ is $\Omega (n^{k+1})$ 2d answered Show that an inverse of a bijective linear map is a linear map. Feb 6 answered Expected value problem with cars on a highway Feb 5 answered Prove that a one-color $K_4$ exists in a two-color $K_{18}$ Feb 5 answered Is $\mathbb{Z}[x]/(x^2 + x + 1, 9)$ isomorphic to $\mathbb{F}_{81}$? Feb 4 answered Show that there exists c such that $f(c)=c^2$ Feb 4 answered Seeking non-inductive, combinatorial proof of the identity $1^2 + 2^2 + 3^2 + \cdots + n^2 = \frac{n(n + 1)(2n + 1)}{6}$ Feb 3 answered Prove that if $n$ is odd, then $-n$ is odd. Feb 2 answered Inductive factorial formula proof - can't figure out how to finish proof Feb 1 answered The only positive integers that divide successive numbers of the form $n^2+3$ are $1$ and $13$ Feb 1 answered How many numbers between $0$ and $1,000,000$ have exactly one digit equal to $9$ and the sum of digits equal $13$? Feb 1 answered Find the remainder when ${{5^5}^5}^5$ is divided by $24$ Feb 1 answered Show that for $p \neq 2$ not every element in $\mathbb{Z}/p\mathbb{Z}$ is a square. Feb 1 asked Mathematical usage of “$\dots$” during enumeration, is it ok to be imprecise? Jan 31 answered Is there an expression for the sum of $\binom nr^2$ for each $n$? Jan 31 answered Proof that $ax+by+cz=0$ has infinitely many solutions. Jan 31 answered Numbers written as $a^b+b$ for $a,b\geq 2$