New posts in geometry

The case of Captain America's shield: a variation of Alhazen's Billard problem

geometry trigonometry algebraic-geometry recreational-mathematics triangles

Rotated coordinates on a unit sphere

matrices geometry linear-transformations spherical-coordinates spherical-geometry

Proving $\frac{1}{\cos^2\frac{\pi}{7}}+ \frac {1}{\cos^2\frac {2\pi}{7}}+\frac {1}{\cos^2\frac {3\pi}{7}} = 24$

geometry trigonometry polynomials complex-numbers roots-of-unity

Is there a plane algebraic curve with just 3-fold rotational symmetry, but without reflection symmetry?

geometry algebraic-geometry invariant-theory

Derive parametric equations for sphere

geometry parametric

Why do trapezium and trapezoid have inverted meanings in the US?

geometry reference-request terminology math-history

an important property of an ellipse

geometry conic-sections

What is (fundamentally) a coordinate system ?

linear-algebra geometry vector-spaces 3d coordinate-systems

Reflections on a sphere

geometry 3d reflection spheres

Dividing a curve into chords of equal length

geometry

Ruby Koan 151 raising exceptions

ruby geometry

How do you know if a line is straight?

geometry geometric-construction

Proof of golden rectangle inside an Icosahedron

geometry golden-ratio

Intuition on the direction of steepest ascent always being orthogonal to the level set of the function

geometry multivariable-calculus soft-question vector-analysis intuition

Law of Cosines: Proof Without Words

geometry trigonometry

If a subset of the square grid can be tiled by $1\times n$ rectangles for every $n$, can it be tiled by infinite rays?

geometry logic tiling polyomino

Finding the distance between two triangles, one inside the other

geometry

Find the control point of a quadratic bezier curve with known maximum curve value

geometry polynomials bezier-curve

Parametrization of $n$-spheres

general-topology geometry analysis differential-geometry differential-topology

Covering one square by three smaller squares

geometry