求救~~~請問此題過程??

2016-01-17 2:16 am

回答 (1)

2016-01-17 2:42 am
✔ 最佳答案
Sol
第一次後濃度=0.25*0.9
第二次後濃度=0.25*0.9^2

0.25*0.9^n<0.02
0.9^n<0.02/0.25
0.9^n<0.08
log0.9^n<log0.08
nlog(9/10)<log(8/100)
n(2log3-1)<log8-log100
n<(log8-log100)/(2log3-1)
n<(log100-3log2)/(1-2log3)
n<(2-3*0.3040)/(1-2*0.4771)
n<1.398/0.0458
n<30.52
n<=31


收錄日期: 2021-04-30 20:11:39
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20160116181654AAYThL6

檢視 Wayback Machine 備份