作者matmoki (户田最高)
看板trans_math
标题Re: [微分] 应用问题
时间Tue Nov 25 17:28:46 2008
※ 引述《s1990716 (小婷)》之铭言：
: A(square)baseball diamond has sides that are 90 feet along. A player 26 feet
: from third base is running at a speed of 30 feet per second. At what rate is
: the player's distance from home plate changing ?
: 不清楚要怎麽设式呢......
: 请帮忙解惑~
A到本垒板 = L A到三垒 = S = 26
L^2+(22.5)^2=S^2
dL S dS
-- = ----2-----2-- -- ≒ 60 dS/dt=30
dt √(S -22.5 ) dt
一般这种题目数字都会设计漂亮一点 这题真丑 ^^"
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