Tutors Answer Your Questions about Exponential-and-logarithmic-functions (FREE)
Question 59163: Hello, could you help me with writing a function, all I need is the function to understand it, I dont need an explanation.
A radioactive isotope is produced, it takes 20 minutes to double the existing amount of the isotope. write an equation for the number of isotopes, n, as a function of time.
thanks.
Click here to see answer by stanbon(75887)  |
Question 60735: What rate of interest to the nearest tenth of a percent compounded quarterly is needed for an investment of $1500 to grow to $2700 in 10 years?
I am not sure which formula to use: A=p(1+r)^t or A=P(1+r/4)^4t. I can not get either formula to work out correctly. Thank you for your help.
Click here to see answer by josmiceli(19441)  |
Question 60825: Please help me with the following problem:
2log(y+2)=log(y+2)-log12
What I tried -
log(y+2)-log12-log(y+2)^2
y+2/12(y+2)^2=1
y+2/12y^2+48y+48=1
y+2=12y^+48y+48
12y^2+47y+46=0
That's where I got! - please help!
Click here to see answer by Nate(3500) |
Question 61669: The half- life of a radioactive substance is one hundred ninety-four days. How many days will it take for eighty percent of the substance to decay?
I used the half life decay formula.
my formula for the problem read...
0.8Nsubscript0=Nsubscript0*(1/2)superscript(t/194)
the result was about 62.5,
is this correct.
=]
Click here to see answer by Edwin McCravy(20059)  |
Question 61670: The half- life of a radioactive substance is one hundred ninety-four days. How many days will it take for eighty percent of the substance to decay?
I used the half life decay formula.
my formula for the problem read...
0.8Nsubscript0=Nsubscript0*(1/2)superscript(t/194)
the result was about 62.5,
is this correct.
=]
Click here to see answer by ankor@dixie-net.com(22740)  |
Question 61664: I need help on this homeowrk question. Thank you!
FOr each of the following relations, sketch the graph of the relation and its inverse and write an eqation for the inverse.
y=x squared -2x-3
I can graph it using my calculator but i cant seem to figure out the inverse equation
Click here to see answer by stanbon(75887) |
Question 61834: Exponential and Logarithmic Functions
(1)Let f(x) = 2^x , g(x) = (1/8)^x, and h(x) = log sub 2(x). Find each of the following:
f(3)
f(-2)
f(1/2)
g(2)
g(-1)
g(1/3)
h(2)
h(1/2)
(2) Solve each of the following equations for the given variable
(a) 2^a = 16
(b) 3^z = 1/9
(c) 9^n = 3
(d) (1/5)^x = 25
Click here to see answer by funmath(2933) |
Question 61836: Exponential and Logarithmic Functions
(1) Let f(z) = 3^z
(a) Find what value of z does f(z) = 81?
(b) For what value of z does f(z) = 1?
(2) Graph each of the following. Give coordinates of at least 3 points on each graph.
(a) y = 3^x
(b) y = logsub 3 x
(3) The population of a large U.S. city is growing according to the function P = 1,400,000(1.023)^t, where t is the number of years since 1990.
(a) What was the population in 1990?
(b) What will the population be in 2007 according to this formula?
(c) What does the value of 1.023 mean in the context of the problem?
Click here to see answer by funmath(2933) |
Question 61836: Exponential and Logarithmic Functions
(1) Let f(z) = 3^z
(a) Find what value of z does f(z) = 81?
(b) For what value of z does f(z) = 1?
(2) Graph each of the following. Give coordinates of at least 3 points on each graph.
(a) y = 3^x
(b) y = logsub 3 x
(3) The population of a large U.S. city is growing according to the function P = 1,400,000(1.023)^t, where t is the number of years since 1990.
(a) What was the population in 1990?
(b) What will the population be in 2007 according to this formula?
(c) What does the value of 1.023 mean in the context of the problem?
Click here to see answer by hotrodd(18) |
Question 61674: Please help !!!
a sum of 100,000 is invested in a bank at a rate of 6 % p.a .
a)assume the amount of money invested for 5 years .
b)detemine the amountthat will be withdrawn if the compunding will be done
i) once a year ii) monthly iii) continously
formula ;
A = p ( 1+r) ^ n
Click here to see answer by stanbon(75887) |
Question 62378: This says to use a calculator to find the value to four decimal places.
1n 0.005.
and then separately find y to four decimal places if possible.
log y = 0.926
I am absolutely clueless on these although I have reviewed it in the book. Can anyone help me out?
Click here to see answer by Earlsdon(6294) |
Question 62376: I have tried to set this one up but have been unsuccessful in getting the solution. Can anyone help me out?
Find each value of x.
log1/2 16 =x
the 1/2 next to the log in like an exponent but below it. I hope it is clear enough. Thanks in advance!
Click here to see answer by stanbon(75887) |
Question 62418: find the constant rate of increase k, when the expotential function consist of x values of 0,1,2,3,4,5. and y values 2,4,8,16,32,64
Click here to see answer by uma(370) |
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