How to prove this $\pi$ formula?
134633
How to sum this series for $\pi/2$ directly?
65562
Proving the inequality $\arctan\frac{\pi}{2}\ge1$
1859
Proving $\arctan(\sqrt{x^2+1}-x)=\frac{\pi}{4}-\frac{1}{2}\arctan(x)$
8358
Prove $\int_{0}^{\pi/2} \ln \left(x^{2} + (\ln\cos x)^2 \right) \, dx=\pi\ln\ln2 $
85311
Proving that $e^{\pi}-{\pi}^e\lt 1$ without using a calculator
25967
Prove $\csc(x)=\sum_{k=-\infty}^{\infty}\frac{(-1)^k}{x+k\pi}$
107296
How do I prove $\int_{-\infty}^{\infty}{\cos(x+a)\over (x+b)^2+1}dx={\pi\over e}{\cos(a-b)}$?
58526
Proving Legendre's Formula
30897
$\pi(x)\geqslant\frac{\log x}{2\log2}$ for all $x\geqslant2.$
107924
Prove (or derive) the de Polignac formula for the prime decomposition of $n!$
60230
Prove that $\frac{1+\sin\theta+i\cos\theta}{1+\sin\theta-i\cos\theta}=\sin\theta+i\cos\theta$
15477
Nice proofs of $\zeta(4) = \frac{\pi^4}{90}$?
61794
Interesting and unexpected applications of $\pi$
146047
Proving that $\cos(2\pi/n)$ is algebraic
54512
How do I prove: $\cos (\theta + 90^\circ) \equiv - \sin \theta $
109295
Proving $1-\exp(-4x^2/ \pi) \ge \text{erf}(x)^2$
46353
Proof that $\cos(\pi/3)=1/2$