[積分] 超難

[chingyes (axsazxc)]

The growth rate of certain bacteria culture is proportional to its  size .


If the bacteria culture double in size every 20 minutes

, how long will it take for the culture  to increase twelve-fold?


請神人幫忙＠＠

--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 61.31.138.157
※ 編輯: chingyes        來自: 61.31.138.157        (12/05 08:59)
→ yhliu:P'(t)=kP(t) and P(t+20)=2P(t)
→ yhliu:求 t* 使 P(t*)=13P(0).
→ chingyes:good!