Re: [理工] [工數]-一個很笨的微積分問題...

[fpfax999 (明林團丁)]

           1
    u = -------
         cosy

                   -1
對x微   du   d(cosy  )   dy
======> -- =  ------  * ---
        dx      dy       dx

                 -1
            d(cosy )  d(cosy)
======>u' = ------- * ------- * y' (chain rule)
             d(cosy)    dy
                    siny
=======>    u' = ----------y'
                  (cosy)^2



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