The dot product returns a scalar that measures alignment, while the cross product returns a vector perpendicular to two three-dimensional vectors. Learn the formulas, geometric meaning, right-hand rule, projections, work, area, plane normals, torque, flux, scalar triple products, Lagrange’s identity, and complete worked examples.
Fourier series reveal how complex periodic signals can be rebuilt from simple sine and cosine waves. Learn how harmonics, Fourier coefficients, orthogonality, partial sums, and frequency-domain thinking connect to sound, heat flow, PDEs, engineering, and quantum mechanics.
