$$$\csc{\left(x \right)}$$$의 이차 도함수
사용자 입력
$$$\frac{d^{2}}{dx^{2}} \left(\csc{\left(x \right)}\right)$$$을(를) 구하시오.
풀이
제1도함수 $$$\frac{d}{dx} \left(\csc{\left(x \right)}\right)$$$를 구하세요
코시컨트의 도함수는 $$$\frac{d}{dx} \left(\csc{\left(x \right)}\right) = - \cot{\left(x \right)} \csc{\left(x \right)}$$$:
$${\color{red}\left(\frac{d}{dx} \left(\csc{\left(x \right)}\right)\right)} = {\color{red}\left(- \cot{\left(x \right)} \csc{\left(x \right)}\right)}$$따라서, $$$\frac{d}{dx} \left(\csc{\left(x \right)}\right) = - \cot{\left(x \right)} \csc{\left(x \right)}$$$.
다음으로, $$$\frac{d^{2}}{dx^{2}} \left(\csc{\left(x \right)}\right) = \frac{d}{dx} \left(- \cot{\left(x \right)} \csc{\left(x \right)}\right)$$$
상수배 법칙 $$$\frac{d}{dx} \left(c f{\left(x \right)}\right) = c \frac{d}{dx} \left(f{\left(x \right)}\right)$$$을 $$$c = -1$$$와 $$$f{\left(x \right)} = \cot{\left(x \right)} \csc{\left(x \right)}$$$에 적용합니다:
$${\color{red}\left(\frac{d}{dx} \left(- \cot{\left(x \right)} \csc{\left(x \right)}\right)\right)} = {\color{red}\left(- \frac{d}{dx} \left(\cot{\left(x \right)} \csc{\left(x \right)}\right)\right)}$$$$$f{\left(x \right)} = \cot{\left(x \right)}$$$와 $$$g{\left(x \right)} = \csc{\left(x \right)}$$$에 대해 곱의 미분법칙 $$$\frac{d}{dx} \left(f{\left(x \right)} g{\left(x \right)}\right) = \frac{d}{dx} \left(f{\left(x \right)}\right) g{\left(x \right)} + f{\left(x \right)} \frac{d}{dx} \left(g{\left(x \right)}\right)$$$을 적용하십시오:
$$- {\color{red}\left(\frac{d}{dx} \left(\cot{\left(x \right)} \csc{\left(x \right)}\right)\right)} = - {\color{red}\left(\frac{d}{dx} \left(\cot{\left(x \right)}\right) \csc{\left(x \right)} + \cot{\left(x \right)} \frac{d}{dx} \left(\csc{\left(x \right)}\right)\right)}$$코시컨트의 도함수는 $$$\frac{d}{dx} \left(\csc{\left(x \right)}\right) = - \cot{\left(x \right)} \csc{\left(x \right)}$$$:
$$- \cot{\left(x \right)} {\color{red}\left(\frac{d}{dx} \left(\csc{\left(x \right)}\right)\right)} - \csc{\left(x \right)} \frac{d}{dx} \left(\cot{\left(x \right)}\right) = - \cot{\left(x \right)} {\color{red}\left(- \cot{\left(x \right)} \csc{\left(x \right)}\right)} - \csc{\left(x \right)} \frac{d}{dx} \left(\cot{\left(x \right)}\right)$$코탄젠트의 도함수는 $$$\frac{d}{dx} \left(\cot{\left(x \right)}\right) = - \csc^{2}{\left(x \right)}$$$:
$$\cot^{2}{\left(x \right)} \csc{\left(x \right)} - \csc{\left(x \right)} {\color{red}\left(\frac{d}{dx} \left(\cot{\left(x \right)}\right)\right)} = \cot^{2}{\left(x \right)} \csc{\left(x \right)} - \csc{\left(x \right)} {\color{red}\left(- \csc^{2}{\left(x \right)}\right)}$$간단히 하시오:
$$\cot^{2}{\left(x \right)} \csc{\left(x \right)} + \csc^{3}{\left(x \right)} = \left(-1 + \frac{2}{\sin^{2}{\left(x \right)}}\right) \csc{\left(x \right)}$$따라서, $$$\frac{d}{dx} \left(- \cot{\left(x \right)} \csc{\left(x \right)}\right) = \left(-1 + \frac{2}{\sin^{2}{\left(x \right)}}\right) \csc{\left(x \right)}$$$.
따라서 $$$\frac{d^{2}}{dx^{2}} \left(\csc{\left(x \right)}\right) = \left(-1 + \frac{2}{\sin^{2}{\left(x \right)}}\right) \csc{\left(x \right)}$$$.
정답
$$$\frac{d^{2}}{dx^{2}} \left(\csc{\left(x \right)}\right) = \left(-1 + \frac{2}{\sin^{2}{\left(x \right)}}\right) \csc{\left(x \right)}$$$A