25 Genius mathematicians who never published anything 24 How can I write the numbers 5 and 7 as some sequence of operations on three 9s? 19 Examples of mathematical results discovered “late” 16 Question definition: If I take any three vectors… 15 “Simple” beautiful math proof

### Reputation (1,793)

 +20 Calculate angle between two lines +236 How acceptable is an ellipsis “…” in formal mathematics? +50 Find perpendicular distance from point to line in 3D? +10 Juxtapose two triangles with a common edge

### Questions (4)

 22 How acceptable is an ellipsis “…” in formal mathematics? 6 Name of a shape that is intersected once by each ray that starts at a given point 2 Is there a term for the opposite of an interpolation? 1 What are the rules for geometrical transformations on entries of matrices that describe geometrical transformations?

### Tags (41)

 31 elementary-number-theory × 4 5 exponential-function 25 geometry × 10 4 contest-math 18 linear-algebra × 2 3 angle × 2 6 calculus × 4 3 logic × 2 5 logarithms 3 algorithms × 2