16 Are proofs by contradiction really logical? 6 Find $x,y,z>0$ such that $x+y+z=1$ and $x^2+y^2+z^2$ is minimal 4 In how many ways can a $31$ member management be selected from $40$ men and $40$ women so that there is a majority of women? 3 Counting ordered pair $(m,n)$ in natural numbers satisfying an inequality 3 Understanding a proof of RREF uniqueness

### Reputation (2,741)

 +10 How to find the equidistant middle point for 3+ points on an arbitrary polygon? +10 Knights and Knaves B: “B is a knight only if A is a knight” +10 Multivariable Calculus: Evaluating a Line Integral Using Green's Theorem With Single Differentiable +15 Application of derivative: maximum porblems.

### Tags (117)

 25 linear-algebra × 38 12 geometry × 11 21 logic × 5 11 multivariable-calculus × 8 17 calculus × 13 10 graph-theory × 7 16 intuitionistic-logic 9 matrices × 14 16 proof-theory 9 combinatorics × 7

### Bookmarks (180)

 388 The Ring Game on $K[x,y,z]$ 94 lim sup and lim inf of sequence of sets. 93 Chatting about mathematics (with real-time LaTeX rendering) 84 How to solve these two simultaneous “divisibilities” : $n+1\mid m^2+1$ and $m+1\mid n^2+1$ 80 In $n>5$, topology = algebra