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Tutors Answer Your Questions about logarithm (FREE)
Question 86088: The loudness level of a sound can be expressed by comparing the sound’s intensity to the intensity of a sound barely audible to the human ear. The formula D=10(log I-logI^0) describes the loudness level of a sound, D, in decibels, where I in the intensity of the sound, in watts per meter^2 , and I^0 is the intensity of a sound barely audible to the human ear.
A. Express the formula so that the expression in parentheses is written as a single logarithm.
B. Use the form of the formula form part (A) to answer this question: If a sound has intensity 100 times the intensity of a softer sound, how much larger on the decibel scale is the loudness level of the more intense sound?
Click here to see answer by scianci(186)   |
Question 86089: Students in a psychology class took a final examination. As a part of an experiment to see how much of the course they remembered over time, they took equivalent forms of the exam in monthly intervals thereafter. The average score, f(t), for the group t months was modeled by the function f(t) = 76 - 18 log (t+1), where 0< or equal to t < or equal to 12.
A) What was the average score when the exam was first given?
B) What was the average score after 4 months? 1 year?
Click here to see answer by bucky(1732) |
Question 86387: 4) For a fixed rate, a fixed principal amount, and a fixed compounding cycle, the return is an exponential function of time. Using the formula, , let r = 8%, P = 1, and n = 1 and give the coordinates (t,A) for the points where t = 0, 1, 2, 3, 4. Round your answer to the hundredth's place.
a) Show coordinates in this space.
Show work in this space.
b) Show graph here.
b) Most calculators have 2 different logs on them: log, which is base 10, and ln, which is base e. In computer science, digital computers are based on the binary numbering system which means that there are only 2 numbers available to the computer, 0 and 1. When a computer scientist needs a logarithm, he needs a log to base 2 which is not on any calculator. To find the log of a number to any base, we can use a conversion formula as shown here:
Using this formula, find . Round your answer to the hundredth's place.
Answer:
Show work in this space.
Click here to see answer by jim_thompson5910(13785) |
Question 86591: I'm normally quite good with logarithms but for some reason this question really stumped me. I can't find any examples in the book or my notes.
5^log57 log base 5 of 7 is all in exponential notation and I have no idea how to solve this.
Please help if you can.....
Click here to see answer by stanbon(26252) |
Question 86806: In 2000, the population of Israel was approximately 6.04 million and by 2050 it is projected to grown to 10 million. Use the exponential growth model A = Aoe^kt, in which t is the number of years after 2000, to find an exponential growth function that models the data.
In which year will Israel's population be 9 million?
Click here to see answer by stanbon(26252) |
Question 86804: The logistic growth function
P(x) = 90/1+271e^-0.122x
models the percentage, P(x), of Americans who are x years old with some coronary heard disease.
QUESTION: What percentage of 80-year-olds have some coronary heart disease?
Click here to see answer by stanbon(26252) |
Question 86866: Most calculators have 2 different logs on them: log, which is base 10, and ln, which is base e. In computer science, digital computers are based on the binary numbering system which means that there are only 2 numbers available to the computer, 0 and 1. When a computer scientist needs a logarithm, he needs a log to base 2 which is not on any calculator. To find the log of a number to any base, we can use a conversion formula as shown here:
Using the formula, find log2 1000. Round your answer to the hundredths place.
Click here to see answer by Nate(3495) |
Question 87048: The demand function for the price of a certian type of computer software is given by d=750e^(-0.0005x) where d is the price in dollars and x is the number of pieces. How many pieces will be in demand when the price is $200? Round to the nearest whole number.
*I thought put the $200 in for d. Then I am just stuck, I have NO clue where to go from here! word problems....KILL me! Thanks SOOOO much for any help!
Click here to see answer by jim_thompson5910(13785) |
Question 87063: The number of men dying of AIDS (in thousands) since 1987 is modeled by y= 17.3 + 10.06(lnx), where x, represents the number of years after 1987. Use this model to predict the number of AIDS deaths among men in 2008. Round to the nearest hundres men.
Click here to see answer by jim_thompson5910(13785) |
Question 87056: The logistic growth model P(t)=1270/1+27.22e^-0.348t represents the population of a bacterium in a culture tube after "t" hours.
A) What was the initial amount of bacteria in the population?
B)After how many hours is the population of bacteria 1000? Round to the nearest hour.
C) What is the limitig size of P(t), the poluation of bacterium?
* For B) I put 1000 in for "P" and C) I think the answer would be 1270...right?
Click here to see answer by Nate(3495) |
Question 87053: The size P of a small herbivore population at time t, in years obeys the function P(t)=500e^0.22t, if they have enough food and the predator population stays the same.
A) After how many years will the population reach 2500? Round to the nearest tenth.
B)What is the population after 2 and a half years. Round to the nearest whole number.
* I came up with putting 2500 in for "P" for part A, then I can't solve it right! The second part I thought put 2.5 years in for "t"...is that even right? I am SOOOOO lost! Sorry! Thanks! :)
Click here to see answer by Nate(3495) |
Question 87050: Osmium has a radioactive isotope that has a half life of 15.4 days. If one gram of the isotope is present now, then amount A (in grams) present after t days is A=(1/2)^t/15.4
How many days will pass before there is 0.73 grams of the isotope present? Round to the nearest day!
*So I thought to put the 0.73 in for A, and help would be fabulous! THANKS!
Click here to see answer by scott8148(3382)  |
Question 87121This question is from textbook
: Create a table of values for the following logarithmic functions and graph:
a. f(x)=log(subscript)4(x+3)
b. f(x)=log(subscript)4x+3
I repeatedly get the wrong graphs for each equation. Frustrated.This question is from textbook
Click here to see answer by rapaljer(3610) |
Question 87284This question is from textbook
: Please explain to me the difference between a logarithm of a product and the product of logarithms, and provide me with examples of each. I really appreciate your help.This question is from textbook
Click here to see answer by rapaljer(3610) |
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