Lectures related to Acute and obtuse triangles

Explains root system classification and fundamental regions in Coxeter groups.

Explains the relations in a right-angled triangle involving trigonometric functions.

Explores symmetry in modern geometry, emphasizing reflections, rotations, and practical applications in computer-aided design.

Covers polygonal lines, polygons, separation of the plane, and triangle distances.

Covers surface integrals with a focus on regular parametrization and the importance of understanding the normal vector.

Explores orthogonality, scalar product, and orthonormal bases in vector spaces.

Explores complex numbers, including modulus, conjugation, and Euler formula.