$$$- x \sin{\left(\frac{1}{2} \right)} + 1$$$的导数
您的输入
求$$$\frac{d}{dx} \left(- x \sin{\left(\frac{1}{2} \right)} + 1\right)$$$。
三角函数的参数应以弧度表示。若要以角度输入参数，请将其乘以 pi/180，例如把 45° 写为 45*pi/180，或者使用带有 'd' 的相应函数，例如把 sin(45°) 写为 sind(45)。
解答
和/差的导数等于导数的和/差：
$${\color{red}\left(\frac{d}{dx} \left(- x \sin{\left(\frac{1}{2} \right)} + 1\right)\right)} = {\color{red}\left(- \frac{d}{dx} \left(x \sin{\left(\frac{1}{2} \right)}\right) + \frac{d}{dx} \left(1\right)\right)}$$常数的导数是$$$0$$$:
$${\color{red}\left(\frac{d}{dx} \left(1\right)\right)} - \frac{d}{dx} \left(x \sin{\left(\frac{1}{2} \right)}\right) = {\color{red}\left(0\right)} - \frac{d}{dx} \left(x \sin{\left(\frac{1}{2} \right)}\right)$$对 $$$c = \sin{\left(\frac{1}{2} \right)}$$$ 和 $$$f{\left(x \right)} = x$$$ 应用常数倍法则 $$$\frac{d}{dx} \left(c f{\left(x \right)}\right) = c \frac{d}{dx} \left(f{\left(x \right)}\right)$$$：
$$- {\color{red}\left(\frac{d}{dx} \left(x \sin{\left(\frac{1}{2} \right)}\right)\right)} = - {\color{red}\left(\sin{\left(\frac{1}{2} \right)} \frac{d}{dx} \left(x\right)\right)}$$应用幂法则 $$$\frac{d}{dx} \left(x^{n}\right) = n x^{n - 1}$$$，取 $$$n = 1$$$，也就是说，$$$\frac{d}{dx} \left(x\right) = 1$$$：
$$- \sin{\left(\frac{1}{2} \right)} {\color{red}\left(\frac{d}{dx} \left(x\right)\right)} = - \sin{\left(\frac{1}{2} \right)} {\color{red}\left(1\right)}$$因此，$$$\frac{d}{dx} \left(- x \sin{\left(\frac{1}{2} \right)} + 1\right) = - \sin{\left(\frac{1}{2} \right)}$$$。
答案
$$$\frac{d}{dx} \left(- x \sin{\left(\frac{1}{2} \right)} + 1\right) = - \sin{\left(\frac{1}{2} \right)}$$$A