Anonymous
Anonymous asked in 教育與參考考試 · 1 decade ago

各位大大幫幫我...解微積分題目

2.設總利潤函數為P( x) = 320 + 36 x − x 2 (元),試求可得最大利潤之銷售量x,並求其最大利潤。

PS:x2為x的平方

5.設一台公車每小時營運的固定成本為3200 元,當車速為每小時30公里時,一小時的汽油費為1800 元。假設市區行駛時,汽油費是與車速的平方成正比,試求每公里平均成本最低的車速。

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  • 1 decade ago
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    2. P'(x)=36-2x so, P'=0 when x=18 is the maximum.

    when x =18 , P(18) = 320+324=644 is the max.

    5. Money=1800 when V=30 km/hr

    汽油費是與車速的平方成正比 =>

    We know that M/V^2 is a constant. so 1800/30^2 =1800/900 =2

    so, 1800/30 = 60 that means a kilometer worth 60 dollar

    M=2V^2 , M/V =2V is per kilometer worthy

    that is weird.

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