We have [tex]f(x)[/tex] and [tex]g(x)[/tex] where
[tex]f(x)\geq g(x)\geq 0[/tex] on the closed interval [tex][a,b][/tex].
The area enclosed by functions can be 0 if [tex]f(x)=g(x)=n[/tex] where n is constant and [tex]n\geq0[/tex]. Let S denote the surface we must find difference of f and g to find the area encapsulated by f and g.
[tex]S=\int_{a}^{b}f(x)-g(x)dx=\int_{a}^{b}f(x)dx-\int_{a}^{b}g(x)dx[/tex]
Hope this helps.
