#uw/notes #uw/class/math224 - - - - definite integral represents the signed area between a function and the x axis between the two bounds - $\int_{a}^b f(x) dx$ - for functions with one variable - riemann sums: $$\int_{a}^b f(x) dx = \lim_{ n \to \infty } f(x^*_{k}) \Delta x$$ - double integral - $f(x,y)$ - $$\int \int_{R} f(x,y) dA$$ - represents the signed volume between the xy plane and the graph of $z=f(x,y)$ above the region $R$ - defining region - $$R=[a,b] \times [c,d]$$ - x values are between $a$ and $b$ , y values are between $c$ and $d$ - slice up solid into equations that can be integrated with one variable - $$\int \int_{[a,b] \times [c,d]} f(x,y) dA = \int^b_{a} \int^d_{c}f(x,y)dy dx$$ -