Hans Georg Schaathun
Oktober 2016
$$r = x$$
$$h = f(x)$$
$$w = \Delta x$$
$$c = 2\pi r$$
$$V_{\textrm{rør}} \approx (2\pi x)\cdot f(x)\cdot\Delta x$$
$$V \approx \sum_i (2\pi x_i)\cdot f(x_i)\cdot\Delta x$$
$$V = \int_{x_1}^{x_2} (2\pi x)\cdot f(x)\cdot dx$$