| blob | c0aeb3e042ede2b6ee267d606ef558e2381f8b84 |
1 <span class="re3">$$ \<a href="http://www.golatex.de/wiki/index.php?title=%5Csum"><span class="kw1">sum</span></a>_<span class="sy0">{</span><span class="re9">i = 1</span><span class="sy0">}</span>^n a_i = <span class="sy0">\</span><a href="http://www.golatex.de/wiki/index.php?title=%5Cfrac"><span class="kw1">frac</span></a><span class="sy0">{</span><span class="re9">n(a_1 + a_n)</span><span class="sy0">}{</span><span class="re9">2</span><span class="sy0">}</span> $</span>$