求解Question 32 33 35 [複製鏈接]

http://scemoodle.hkbu.edu.hk/file.php/12573/Chapter_1_Revison_Exercises.pdf
thx

請輸入 帳號名稱與密碼 進行登入

32. We are going to put $2500 into an account that earns interest at a rate of 12%. If
we want to have $4000 in the account when we close it how long should we keep
the money in the account if we compound interest 6 times a year.
33. The function P(t) = 100(1.025)^t models the population of a city,^ where t is time in
years and P(t) is the population size in thousands of people. According to this
model, how long would it take the population to double?
(Round answer to nearest year.)
.
35. The pasteurization process, used in food preservation, was developed by the
French scientist Louis Pasteur (1822-1895). He observed that a certain bacteria
population grows in milk by 2% per hour; the function  N(t) N 0(1.02) ^t
= models
such a population, where t is time in hours, N(t) is the population size at time t and
N 0 represents the initial population size (time t=0). How many bacteria will be
present after 1 hour and 45 minutes in a culture containing initially 2,500 bacteria?

呢D咁ge數仲煩過pure

freeze3704:32. We are going to put $2500 into an account that earns interest at a rate of 12%. If
we want to have $4000 in the account when we close it how long should we keep
the money in the account if we compound interest 6 times a year.
33. The function P(t) = 100(1 .. (2011-10-15 22:08) 

好係唔係必須部份黎
m1/m2?

牙笨:好係唔係必須部份黎
m1/m2? (2011-10-16 11:51) 

log only

32. We are going to put $2500 into an account that earns interest at a rate of 12%. If
we want to have $4000 in the account when we close it how long should we keep
the money in the account if we compound interest 6 times a year.

Let Y be number of years
2500 X (1+12%/6) ^ (6Y) >= 4000
                                        Y  >= 3.96
                                            Y=4

33. The function P(t) = 100(1.025)^t models the population of a city,^ where t is time in
years and P(t) is the population size in thousands of people. According to this
model, how long would it take the population to double?
(Round answer to nearest year.)

P(t) = 2P(0)
     P(t)=200
100(1.025)^t=200
                     t=28
出奇的大


35. The pasteurization process, used in food preservation, was developed by the
French scientist Louis Pasteur (1822-1895). He observed that a certain bacteria
population grows in milk by 2% per hour; the function  N(t) N 0(1.02) ^t
= models
such a population, where t is time in hours, N(t) is the population size at time t and
N 0 represents the initial population size (time t=0). How many bacteria will be
present after 1 hour and 45 minutes in a culture containing initially 2,500 bacteria?

N(1.45) = 2500 X(1.02) ^ 1.45
N(1.45) = 2573

有錯不負責