Fermat's principle of least time for reflection and refraction
131493
Why one should follow Snell's law for shortest time?
133609
orthonormal system in a Hilbert space
93820
Fermat's little theorem applied for $n$'th root existence $\!\bmod p$
123799
Calculating the Fourier transform of $f(t)=Ae^{-i\omega_0 t}$
140910
Solving minimization problem $L_2$ IRLS (Iteration derivation)
75580
Derivation of the speed of light using the integral forms of Maxwell's Equations
63782
Snell's law in vector form
99365
UMVUE for $\theta^2$
85774
Looking for the actual reason of refraction explained precisely without analogies
13999
Phase difference in reflection coefficient between S and P polarisation at normal incidence?
83127
Complex ($\mathbb C$) least squares derivation
62413
Reflection across the plane
145592
Deriving the wave equation for electromagnetic waves
79276
Find $\min(\operatorname{trace}(AA^T))$ for invertible $A_{n\times n}$
53506
Cofactor reflection maps greatest proper divisor to least (prime) proper divisor
97032
Does light accelerate or slow down during reflection?
158103
Computing the UMVUE for Uniform$(0,\theta)$