∫ a b ( u p p e r f u n c t i o n − l o w e r f u n c t i o n ) d x , {\displaystyle \int _{a}^{b}(upperfunction-lowerfunction)\,dx,}
if f(x) = upper function and g(x) = lower function
∫ a b ( f ( x ) − g ( x ) ) d x , {\displaystyle \int _{a}^{b}(f(x)-g(x))\,dx,}
