Choose the true statements about calculating the area between two curves.

The two curves must have intersection points in order to calculate the area between the curves.

If $f(x)g(x)$ on an interval $a,b,$ then the area between the curves is equal to ${\displaystyle \underset{a}{\overset{b}{}}}(f(x)-g(x))dx.$

Both $f(x)$ and $g(x)$ must be positive for all xin$[a,b]$ to calculate the area between the curves.

If $f(x)g(x)$ on an interval $a,b,$ then the area between the curves is equal to ${\displaystyle \underset{a}{\overset{b}{}}}(g(x)-f(x))dx.$

If $f(x)g(x)$ on an interval $a,b,$ then the area between the curves is equal to ${\displaystyle \underset{a}{\overset{b}{}}}(f(x)-g(x))dx.$

If $f(x)g(x)$ on an interval $a,b,$ then the area between the curves is equal to ${\displaystyle \underset{a}{\overset{b}{}}}(g(x)-f(x))dx.$