∫ 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,}
ex1: ∫ 0 2 ( 2 x − x 2 ) d x , {\displaystyle \int _{0}^{2}(2x-x^{2})\,dx,}
f(x) = lower function
g(x) = upper function
f(x) = x 2 {\displaystyle x^{2}}
g(x) = 2 x {\displaystyle 2x}
∫ 0 2 ( 2 x − x 2 ) d x , = 2 x 2 2 − x 3 3 ∫ 0 2 {\displaystyle \int _{0}^{2}(2x-x^{2})\,dx,={2x^{2} \over 2}-{x^{3} \over 3}\int _{0}^{2}}
