三角函数.请解答一道应用题.
问题描述：
三角函数.请解答一道应用题.
Solving Exponential Equations
1.The number of bacteria in a culture is doubling every 3.75 hours.How long will it take for the number of bacteria to increase from 30,000 to 7,680,000?
Please show all steps and give details where needed!
Thanks!
答
设：细菌经过x次翻倍后能从30000到7680000
30000 × 2^x = 7680000
2^x = 256
x=8
细菌每次翻倍需要3.75小时,则8次需要8×3.75=30小时.