Aroldo

$f(x)\,\!$ $=\sum _{n=0}^{\infty }a_{n}x^{n}$ Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://en.wikipedia.org/api/rest_v1/":): {\displaystyle = a_0+a_1x+a_2x^2+\cdots}
<math> a^2+b^2=c^2