A formula : [pmath]delim{|}{{1/N} sum{n=1}{N}{gamma(u_n)} - 1/{2 pi} int{0}{2 pi}{gamma(t) dt}}{|} <= varepsilon/3[/pmath]

• [pmath]pi=sum{n=0}{+infty}{{(n!)^2 2^{n+1}}/{(2n+1)!}}[/pmath]
• [pmath]pi=22/7-int{0}{1}{{x^4 (1-x)^4}/{1+x^2}dx}[/pmath]
• [pmath]pi=3/4 sqrt{3}+24 int{0}{1/4}{sqrt{x-x^2}dx}[/pmath]

[pmath]delim{lbrace}{matrix{3}{1}{{3x-5y+z=0} {sqrt{2}x-7y+8z=0} {x-8y+9z=0}}}{~}[/pmath]  [pmath]delim{|}{matrix{3}{3}{a_{1 1} cdots a_{1 n} vdots ddots vdots a_{n 1} cdots a_{n n}}}{|}[/pmath]