mscroggs.co.uk
mscroggs.co.uk

subscribe

Puzzles

Arctan

Prove that \(\arctan(1)+\arctan(2)+\arctan(3)=\pi\).

Show answer & extension

If you enjoyed this puzzle, check out Sunday Afternoon Maths XXXVIII,
puzzles about geometry, or a random puzzle.

Archive

Show me a random puzzle
 Most recent collections 

Advent calendar 2025

Advent calendar 2024

Advent calendar 2023

Advent calendar 2022


List of all puzzles

Tags

perfect numbers determinants gerrymandering irreducible numbers dodecagons binary differentiation numbers tournaments bases christmas factors combinatorics dates grids multiplaction squares 2d shapes mean chocolate 3d shapes consecutive integers wordplay doubling star numbers folding tube maps symmetry money pentagons remainders the only crossnumber tangents range chalkdust crossnumber elections digital products clocks square grids planes triangle numbers multiples circles shapes expansions triangles advent proportion square roots probabilty integers partitions menace decahedra quadrilaterals regular shapes palindromes games balancing products geometry indices people maths cryptic crossnumbers speed probability fractions digital clocks cube numbers shape albgebra geometric means crosswords logic sum to infinity polynomials addition functions trigonometry spheres complex numbers division prime numbers books even numbers routes integration quadratics ave powers crossnumbers surds multiplication algebra xor lists sets ellipses neighbours cryptic clues angles cubics area cards lines hexagons graphs square numbers odd numbers consecutive numbers coins taxicab geometry prime factors floors digits means sequences unit fractions geometric mean pascal's triangle polygons time rectangles parabolas factorials number dice dominos tiling median colouring sums axes arrows volume rugby perimeter calculus averages matrices sport squares medians chess coordinates percentages scales

Archive

Show me a random puzzle
▼ show ▼
© Matthew Scroggs 2012–2026