# All Questions

154 views

49 views

102 views

113 views

### Is multiplication in mixed radix numeral systems complicated?

The wikipedia article on mixed radix numeral systems says Mixed-radix numbers of the same base can be manipulated using a generalization of manual arithmetic algorithms. This sounds like "naive ...
114 views

### Definite integral inequality

Let $f:[a,b] \to R$ be a differentiable function so that $f(b)=0$.Prove that there is a $c \in (a,b)$ which satisfies: $$f'(c) \int_a^c f(t) dt + c \ge \frac{a+b}{2}$$ Any useful ideas that can ...
53 views

### Algebraic element

$K \leq L, a \in L$ I am looking at the proof that if $a$ is algebraic over $K$, then $K(a)=K[a]$ : We show that $K[a]$ is a field, then we have that $K \subseteq K[a] \subseteq K(a) \subseteq L$. ...
50 views

### Matrix Problem about commutative multiplication [duplicate]

The problem is: "Find all $2\times 2$ matrices A that have the property that for any $2\times 2$ matrix B, AB = BA." Given hint: "The given equation must hold for all B. Try matrices B that have ...