calculus - dx (t) dx vs. dx dx - Mathematics Stack Exchange Stack Exchange Network Stack Exchange network consists of 183 Q A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers
What does the dx mean in an integral? [duplicate] It's because an integral means you are summing over a lot of very thin rectangles under a curve The height of the rectangle is f(x) and the width is called $\delta x$ (These two symbols should be read as a single symbol, it doesn't mean $\delta \times x$)
dy dxをxで積分したときの答えを教えて下さい。過程もお願い . . . 流体力学に関する問題です． 十分に長い同心円筒の間に，粘性係数μの非圧縮性流体が満たされており，外円筒は静止しているが，内円筒が一定角速度ωで回転している．この二重円筒の軸は鉛直方向と一致しており，その内半径R1は既知であるが，外半径R2は未知である．また，内円筒を回転
calculus - Why is it considered that $ (\mathrm d x)^2=0 . . . Why is it okay to consider that $(\\mathrm d x)^n=0$ for any n greater than $1$? I can understand that $\\mathrm d x$ is infinitesimally small ( but greater than $0$ ) and hence its square or cube sh
How to prove $dxdy = r dr d \\theta$? - Mathematics Stack Exchange A piece of an annulus swept out by a change of angle $\Delta \theta$ and a change of radius $\Delta r$, starting from a point given by $(r,\theta)$, has area $\Delta \theta \int_r^{r+\Delta r} s ds = \Delta \theta \frac{(r+\Delta r)^2-r^2}{2} = \Delta \theta \left ( r \Delta r + \frac{\Delta r^2}{2} \right )$