Tutors Answer Your Questions about Exponential-and-logarithmic-functions (FREE)
Question 1129512: The population of a particular country was 28 million in 1985.In 1994,it was 32 million. The exponential growth function A=28e^kt describes the population of this country t years after 1985.Use the fact that 9years after 1985 the population increased by 4 million to find k. Round answer three decimal places.
Click here to see answer by josmiceli(19441)   |
Question 1129920: The population P of a fish farm in t years is modeled by the equation
P(t) = 2200/ (1 + 9e^ −0.8t).
What is the initial population of fish?
*I know that the initial population is when t= 0. And so after substituting zero for t, and solving the equation the answer that I got was 5.59. However, when I have replaced 5.59 for t, the answer was completely inaccurate. Could someone help explain how to solve this correctly? Thanks
Click here to see answer by Boreal(15235)  |
Question 1130375: The world population in 1990 was approximately 5.4 billion. The population has been increasing at a rate of 1.6% per year.
a) Write an equation to represent the world population after x number of years.
b) What would the population be in 2005?
Thanks
Click here to see answer by josgarithmetic(39620) |
Question 1130378: A laboratory has a 750g sample of uranium. This substance has a half life of 20 years.
a) Write an equation to represent the mass of the substance after x half lives.
b) how many half-lives will have elapsed in 120 years ?
c) How much of the sample is left after 120 years?
Thank you
Click here to see answer by jim_thompson5910(35256) |
Question 1130384: a)construct a table of values for the exponential function y=2(3)^x
Use values of x from -1 to 3.
b) Graph the equation. Connect the points with a solid line.
c) What is the x-intercetp? What is the y-intercept?
d) What is the asymptote?
e) Using the graph, estimate the value of x when y=18
Thank you
Click here to see answer by MathLover1(20850)  |
Question 1130776: 1. Write an Assembly Program using the Emu8086 that will
a. input a string of Upper case letters from the keyboard
b. store the string in memory
c. then display the equivalent Lower case letters.
(Example: inputting ABC, outputting abc)
2. Modify your program above so that the input string can contain a combination of both lower and
upper case letters and the output will be the string in reverse case.
(Example: inputting AbCD, outputting aBcd)
3. Modify your program above so that the input string can contain both lower and upper case letters
and any other character and the output will be the reverse case string, as well as in reverse
order where all other characters (other than alphabetical) are replaced by the hash sign (‘*’).
(Example: inputting Ab,CDe%*F, outputting f**Edc*Ba)
4. Modify your program (above) so that the output will implement the following alphabet
conversion:
Original A B C D E
=>
… … … … X Y Z
Converted D E F G H A B C
where the alphabets are shifted 3 letters down.
(Example: Inputting Ab,CDe%*F, outputting: i**Hgf*Ed
Click here to see answer by solver91311(24713)  |
Question 1131039: Use the acidity model
pH = −log[H+],
where acidity (pH) is a measure of the hydrogen ion concentration [H+] (measured in moles of hydrogen per liter) of a solution.
Compute [H+] for a solution in which pH = 4.1. (Enter your answer in scientific notation. Round the decimal value to two decimal places.)
Click here to see answer by josgarithmetic(39620) |
Question 1131521: At 4:00 PM, a turkey is taken out of the oven when its internal temperature reaches 375*F. At 4:30 PM, it has cooled to 325*F. If the turkey cools according to exponential decay, what will its temperature be at 5:00 PM (nearest degree)?
Click here to see answer by ikleyn(52800)  |
Question 1131793: Use the formula N=Ie^kt, where N is the number of items of the initial population "I", at the time "t", and "k" is the growth constant equal to the percent of growth per unit of time. A certain radioactive isotope has a half-life of approximately 1750 years. How many years would be required for a given amount of this isotope to decay to 25% of that amount?
Click here to see answer by Boreal(15235) |
Question 1132003: Use the formula N=Ie^kt, where "N" is the number of items in terms of the initial population "I", at time "t", and "k" is the growth constant equal to the percent of growth per unit of time. There are currently 67 million cars in a certain country, decreasing by 5.4% annually. How many years will it take for this country to have 52 million cars? Round to the nearest year.
Click here to see answer by josgarithmetic(39620) |
Question 1132281: population is 1,803,077 r0.009 n10
p * 1.09373=1,972,086 n=10
double p=3,606,154 r1.009 n10
How do I solve the log part?
log2=log(1.009)n
log2=nlog(1.009)
/ both sides by (1.009) This is where I am completely lost. Please help!
Click here to see answer by Alan3354(69443)  |
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Older solutions: 1..45, 46..90, 91..135, 136..180, 181..225, 226..270, 271..315, 316..360, 361..405, 406..450, 451..495, 496..540, 541..585, 586..630, 631..675, 676..720, 721..765, 766..810, 811..855, 856..900, 901..945, 946..990, 991..1035, 1036..1080, 1081..1125, 1126..1170, 1171..1215, 1216..1260, 1261..1305, 1306..1350, 1351..1395, 1396..1440, 1441..1485, 1486..1530, 1531..1575, 1576..1620, 1621..1665, 1666..1710, 1711..1755, 1756..1800, 1801..1845, 1846..1890, 1891..1935, 1936..1980, 1981..2025, 2026..2070, 2071..2115, 2116..2160, 2161..2205, 2206..2250, 2251..2295, 2296..2340, 2341..2385, 2386..2430, 2431..2475, 2476..2520, 2521..2565, 2566..2610, 2611..2655, 2656..2700, 2701..2745, 2746..2790, 2791..2835, 2836..2880, 2881..2925, 2926..2970, 2971..3015, 3016..3060, 3061..3105, 3106..3150, 3151..3195, 3196..3240, 3241..3285, 3286..3330, 3331..3375, 3376..3420, 3421..3465, 3466..3510, 3511..3555, 3556..3600, 3601..3645, 3646..3690, 3691..3735, 3736..3780, 3781..3825, 3826..3870, 3871..3915, 3916..3960, 3961..4005, 4006..4050, 4051..4095, 4096..4140, 4141..4185, 4186..4230, 4231..4275, 4276..4320, 4321..4365, 4366..4410, 4411..4455, 4456..4500, 4501..4545, 4546..4590, 4591..4635, 4636..4680, 4681..4725, 4726..4770, 4771..4815, 4816..4860, 4861..4905, 4906..4950, 4951..4995, 4996..5040, 5041..5085, 5086..5130, 5131..5175, 5176..5220, 5221..5265, 5266..5310, 5311..5355, 5356..5400, 5401..5445, 5446..5490, 5491..5535, 5536..5580, 5581..5625, 5626..5670, 5671..5715, 5716..5760, 5761..5805, 5806..5850, 5851..5895, 5896..5940, 5941..5985, 5986..6030, 6031..6075, 6076..6120, 6121..6165, 6166..6210, 6211..6255, 6256..6300, 6301..6345, 6346..6390, 6391..6435, 6436..6480, 6481..6525, 6526..6570, 6571..6615, 6616..6660, 6661..6705, 6706..6750, 6751..6795, 6796..6840, 6841..6885, 6886..6930, 6931..6975, 6976..7020, 7021..7065, 7066..7110, 7111..7155, 7156..7200, 7201..7245, 7246..7290, 7291..7335, 7336..7380, 7381..7425, 7426..7470, 7471..7515, 7516..7560, 7561..7605, 7606..7650, 7651..7695, 7696..7740, 7741..7785, 7786..7830, 7831..7875, 7876..7920, 7921..7965, 7966..8010, 8011..8055, 8056..8100, 8101..8145, 8146..8190, 8191..8235, 8236..8280, 8281..8325, 8326..8370, 8371..8415, 8416..8460, 8461..8505, 8506..8550, 8551..8595, 8596..8640, 8641..8685, 8686..8730, 8731..8775, 8776..8820, 8821..8865, 8866..8910
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