Tutors Answer Your Questions about Exponential-and-logarithmic-functions (FREE)
Question 967422: Can you help me solve this problem?
A biologist isolates two strains of a particular virus and monitors the growth of each, starting with samples of 0.01 gram. Strain A increases by 10% in 8 hours and strain B increases by 12 % in 9 hours. Find the hourly growth factor for each strain to compare which strain of virus grows more rapidly?
Thank you
Click here to see answer by josgarithmetic(39620)  |
Question 968704: In the absence of predators, the natural growth rate of rabbits is
4% per year. A population begins with 100 rabbits. The function
f(x) = 100(1.04)^x gives the population of rabbits in x years.
a. How long will it take the population of rabbits to double?
b. How long will it take the population of rabbits to reach 1000?
Click here to see answer by josgarithmetic(39620) |
Question 968704: In the absence of predators, the natural growth rate of rabbits is
4% per year. A population begins with 100 rabbits. The function
f(x) = 100(1.04)^x gives the population of rabbits in x years.
a. How long will it take the population of rabbits to double?
b. How long will it take the population of rabbits to reach 1000?
Click here to see answer by amarjeeth123(570) |
Question 969299: Hello tutor, please help me solve this. I tried and came up with the second one but I am not sure:
Which is the better deal, $10,000 invested at 5%, compounded yearly, for 20 years, or $5,000 invested at 10%, compounded continuously, for 20 years?
Click here to see answer by Boreal(15235)  |
Question 969299: Hello tutor, please help me solve this. I tried and came up with the second one but I am not sure:
Which is the better deal, $10,000 invested at 5%, compounded yearly, for 20 years, or $5,000 invested at 10%, compounded continuously, for 20 years?
Click here to see answer by solver91311(24713)  |
Question 970274: One gram of Pu-238 generates 0.56 watts of thermal power and has a half life of 87.7 years. The generator that converts thermal power to to electrical power for the probe's instruments operates at 6% efficiency(i.e. 1 watt of thermal power generates 0.06 watts of electrical power). The instruments on the spacecraft require 85 watts of electrical power and need to operate for 19 years to complete the mission.
How many whole grams of Pu-238 are required to complete the mission?
I assumed I should be using either the half life A=Ao(1/2)^(t/h)
But is the A grams or watts?
Or should I be using the interest formula?
I am having trouble setting up the problem. Thanks!
Click here to see answer by ankor@dixie-net.com(22740)  |
Question 970282: Factor completely: sin^3(x) + cos^3(x)
Select one:
a. (sin(x) + cos(x))(sin^2(x) - sin(x)cos(x) + cos^2(x))
b. (sin(x) + cos(x))(sin^2(x) + sin(x)cos(x) + cos^2(x))
c. sin(x)cos(x)[sin^2(x) + cos^2(x)]
d. (sin(x)+cos(x))(sin^2(x) - cos^2(x))
Click here to see answer by Alan3354(69443)  |
Question 970283: The exposure volume EV of a photograph can be calculated from the time, t, in seconds that the shutter was open and the value of the f-stop,f, the picture was taken at using by using the logarithmic equation:
EV=logbase2(f^2/t)
use the properties of logarithms to expand the formula for EV:
For this part I did: 2 Logbase2 f - logbase2 t
b. Keith takes a picture of a waterfall with a shutter speed of 1/60 second at f/5.657. he likes the exposure of his picture, but want to leave the shutter open four times as long to better capture the motion of the water. What f-stop should he use on his next picture.
This is where I am having some trouble. I started by doing 4(1/60)=1/15 and that is my t. I know I am solving for f, but is 5.657 my EV?
Click here to see answer by stanbon(75887) |
Question 970533: NASA is designing a robotic spacecraft to visit Neptune. The probe will use the radioactive isotope Plutonium-238(Pu-238) as a power source. One gram of Pu-238 generates 0.56 watts of thermal power and has a half-life of 87.7 years. The generator that converts thermal power to electrical power for the probe's instruments operates at 6% efficiency (i.e. 1 watt of thermal power generates 0.06 watts of electrical power). The instruments on the spacecraft require 85 watts of electrical power and need to operate for 19 years to complete the mission.
a. How many whole grams of Pu-238 are required to complete the mission?
b. Discuss how a different generator, operating at 7% efficiency, would affect the amount of Pu-238 required to complete the mission. Use algebra to back up your claim.
c. Suppose NASA wants the mission to last 25 years and has only 2500 grams of Pu-238 available for the probe. To what operating efficiency must the engineers design the generator? Round your answer to the nearest tenth of a percent.
Click here to see answer by ankor@dixie-net.com(22740) |
Question 971718: The speed of light, often denoted by the variable c, is 2.998x10^8 meters per second. Because the distance light travels in one year is so large, in 1838 the German astronomer Bessel coined the term "light year" to represent this distance. Bessel first used this term when he announced that the distance to the star 61 Cygni was 10.3 light years.
Given that there are 3600 seconds in an hour, 24 hours in a day, and approximately 365.24 days in a year, what is the distance to 61 Cygni in meters? Give your answer in scientific notation with 3 decimal places.
I am a little confused with the setup of this problem. Should I multiply c times 3600 times 24 times 365.24 and when I get that answer then multiply it by the 10.3 light years?
Click here to see answer by anand429(138)  |
|
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
|
