Interesting References

• Euler-Lagrange equation for parametric elliptic functional. link

• Arithmetic–geometric mean. link

• What is \(\displaystyle\lim_{n\to\infty}\frac1n \left(\text{maximum value of }\sum_{k=1}^n\sin (kx)\right)\)? link

• A continuous function with divergent Fourier series. link

• Evans-Krylov theorem. link

• Liouville-type theorems for elliptic problems. link

• \(\displaystyle\int\frac{\sin(nx) \sin x}{1-\cos x} \mathrm{~d}x\) by elementary methods. link