定積分

$F'(x)=f(x)$のとき,$f(x)$の$a$から$b$までの定積分（definite integral）を

\[\int_{a}^{b} f(x)dx = F(b)-F(a)=[F(x)]_{a}^{b}\]

と定義する．

Mathematics is the language with which God has written the universe.