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Tutors Answer Your Questions about Exponential-and-logarithmic-functions (FREE)
Question 22250: Hello, I am solving some questions in my textbook and I have seem to fallen into a slump. Please help.
A bacteria called escherichia coli are commonly found in the bladder. Suppose that 3000 of the bacteria are present at time t=0. Then t minutes later, the number of bacteria present can be approximated by n(t)=3000(2)^(t/20) (the t/20 is written in exponent form)
How many bacteria will be present after 10min? 20min? 30min? 40min? 60min?
If I could have someone workout the first few and I can probably get the rest done.
Click here to see answer by stanbon(26259)   |
Question 22516: Here is my equation: 4^x + 6 = 7
Here is what I tried: x + 6log4 = 7log
x (log4 + 6log4) = 7log
x = 7log/log4 + 6log4
I come up with 3.61 but I dont think that is correct.
Here is the other way I was trying to solve it.
ln4^x + 6 = ln 7
x + 6 ln 4 = ln 7
x = ln7/6ln4 = .45 Is that way correct?
Click here to see answer by ilana(236) |
Question 22517: Use properties of logarithms to condense the logarithmic expression.
Write the expression as a single logarithm whose coefficient is 1.
Where possible, evaluate logarithmic expressions.
Here is my problem: log5(x + 4) – log5(x + 1)
log5 x + 4/x + 1
THis is what I got but can you condence it more.
Click here to see answer by ilana(236) |
Question 22517: Use properties of logarithms to condense the logarithmic expression.
Write the expression as a single logarithm whose coefficient is 1.
Where possible, evaluate logarithmic expressions.
Here is my problem: log5(x + 4) – log5(x + 1)
log5 x + 4/x + 1
THis is what I got but can you condence it more.
Click here to see answer by AnlytcPhil(958) |
Question 22532: I have spent about 4 or 5 hours trying to figure this out. I'm trying to identify the inverse function, "f^-1(x)", for the following question, "If f(x)=x^2/(x-1) what is f^-1(x)." I have gotten to x^2=xy-y but have taken many paths from there and seem to be going in circles.
Click here to see answer by stanbon(26259) |
Question 23001: __________________2
log (3x-1)=log (2x )
___8__________8
im sorry i dont really know how to type those on the computer but the to is for 2x squared and the 8s are supposed to be log and then the little 8 thing
I dont really know how to do this stuff so if you could show me one i would know how to do it
Thank you
Click here to see answer by rapaljer(3619) |
Question 22916: I'm having trouble with this text book question can you show me how to solve it
graph parabola with vertex and intercepts
f(X)= xsquared+6X+5 (sorry I dont know how to make a small 2 after the first x)
Click here to see answer by NaiXLG(18) |
Question 22916: I'm having trouble with this text book question can you show me how to solve it
graph parabola with vertex and intercepts
f(X)= xsquared+6X+5 (sorry I dont know how to make a small 2 after the first x)
Click here to see answer by Earlsdon(4898) |
Question 23131: How do you express the Unions of A and B if Set A: {1,3,6,10,15,21} & Set B: {2,4,6,8,10,12}?
Click here to see answer by AnlytcPhil(958) |
Question 23276: i can understand the teacher while he is discussin the lesson but when i have to do the assignment i dont know wat to do, right now we r workin on logarithms and i dont uderstand the exact sloution and the approximate solution, plz i need help the test is soon?
Click here to see answer by stanbon(26259) |
Question 23355: i am being asked to explain the mathematical modeling for the following:
A deer population increases from 140 in 1990 to 365 in 1995.
a) what is the growth rate for the 5 year period?
b) write an equation describing the deer population in terms of the number of 5 year periods?
c) What is the annual growth factor?
d) write an equation describing the deer population in terms of 1 year periods?
e) How can I modify my equation so that the equation used to describe the 5 year population utilizes the annual growth factor?
Click here to see answer by stanbon(26259) |
Question 20786: When "0" is the exponent, how are the numbers effected if the exponent is inside or outside of the parenthesis. Example: (-1/4) with an exponent of zero inside and with an exponent of zero outside the parenthesis)?
Thanks!
Click here to see answer by stanbon(26259) |
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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
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