[考古] 98政大國貿微積分

[kentarosu (肯泰羅)]

98年政大國貿微積分第10題

原考題：http://img638.imageshack.us/img638/9569/22679131.jpg


A ladder 26 ft long leans against a vertical wall. If the lower end is moved
away from the wall at the rate of 5(ft/sec), how fast is the height of the
top decreasing when the the lower end is 10 ft from the wall?

不知道該怎麼解
想請大家幫忙給一些頭緒
若能幫忙詳細解答更佳^^"


                                              拜託了 感謝~


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◆ From: 114.33.56.62
推 a039333780:畢氏定理+全微分
推 a039333780:x^2+y^2=26^2
→ a039333780:對t微分  然後題目給的帶進去
→ a039333780:dx/dt=5  且x=10 故y=24  (畢氏定理)
→ a039333780:只剩下dy/dt待解而已= =
→ a039333780:這題也算長考的題目@@@@