微分(3)の1．(1)の解答

$3$\displaystyle{y=\cos 3x}$
$3$\displaystyle{\begin{array}y&=& \cos u & \vspace{6}\\ \end{array}}$
$3$\displaystyle{\begin{array}u&=& 3x & \vspace{6}\\ \end{array}}$ とおく。
$3$\displaystyle{\begin{array} \frac{\hspace{2} du \hspace{2}}{\hspace{2} dx \hspace{2}} &=&3& \vspace{6}\\ \end{array}}$ かつ
$3$\displaystyle{\begin{array} \frac{\hspace{2} dy \hspace{2}}{\hspace{2} du \hspace{2}} &=& - \sin u & \vspace{6}\\ \end{array}}$ より
$3$\displaystyle{\begin{array}{lll} \frac{\hspace{2} dy \hspace{2}}{\hspace{2} dx \hspace{2}} &=& \frac{\hspace{2} dy \hspace{2}}{\hspace{2} du \hspace{2}}\cdot \frac{\hspace{2} du \hspace{2}}{\hspace{2} dx \hspace{2}} & \vspace{6}\\ &=& $ - \sin u $ \cdot 3 & \vspace{6}\\ &=& - 3\sin 3x & \vspace{6}\\ \end{array}}$
⇒次の問題の解答
⇒ヒント1,ヒント2
⇒微分(3)のTOPへ戻る