Notations mathématiques

`frac(-b+- sqrt(b^(2)-4ac) )(2a) `

`1=0.bar(9) =0.999999...`

`e^(i pi)+1=0`

`((x_(n+1)),(y_(n+1)))=((cos(theta ),-sin(theta )),(sin(theta ),cos(theta ))) ((x_n),(y_n))`

`"et finalement" int_{0}^{pi }{:sin(x) dx:} `