Logarithm Definition and 339 Threads

  1. B

    How can I integrate (1-x)ln(1-x) using integration by parts?

    Hello So I have a problem, which is to use integration by parts to integrate... \int^{1}_{0}(1-x) ln (1-x) dx The way I have been working is it to separate it out into just... \int^{1}_{0}ln (1-x) dx - \int^{1}_{0}x ln (1-x) dx and then integrating by parts on each of these...
  2. N

    Solving a Logarithm: Can't Remember How? Try Here!

    Can't remember how to do this (trying to solve for D): x = b/D + a*log(D) Any takers? Or is this impossible?
  3. D

    Solving Logarithm Overkill: Find Exact Value for ln(ln[e^{e^{5}}])

    Hello again! I have been working on this log, and the longer I work on it, the more confused I get! Here's the problem: Find the exact value for: ln(ln[e^{e^{5}}]) ---- Here's what I've tried so far: e(ln[e^{e^5}}]) e^{x} = ln(e^{e^5}}) e^{x} = e^{e^5}} e^{5} = (2.72)^{5}...
  4. D

    Solve Logarithm Overkill: Find ln(ln[e^{e^{5}}])

    [SOLVED] Logarithm overkill! Hello again! I have been working on this log, and the longer I work on it, the more confused I get! Here's the problem: Find the exact value for: ln(ln[e^{e^{5}}]) ---- Here's what I've tried so far: e(ln[e^{e^5}}]) e^{x} = ln(e^{e^5}}) e^{x} =...
  5. J

    Logarithm Property: Unique or Not?

    Does anyone know if the property of the logarithm function that: log(ab)=log(a)+log(b) is unique to that function? In other words, has it been shown that there can be no other function with that property? -j
  6. P

    Natural Logarithm of Negative Numbers

    Well I came across this when someone asked me this question: (-2)^n = 16 I can clearly see n=4. However, he did this: ln((-2)^n) = ln(16) n*ln(-2) = ln(16) n*ln(2)+n*i*pi = ln(16) How can I show that n=4 from this?
  7. O

    Solving Logarithms: Finding the Solution for ln(x) + ln(y) = 0

    Hi everyone. I know this question is quite simple but I can't wrap my head around it at the moment.. Solve for y: ln(x) + ln(y) = 0 I've tried differentiating both terms and then arranging for y but I get y = -x. The answer is meant to be y = 1/x. Thanks all!
  8. V

    Using the Mean Value Theorem to Solve Equations

    Hi, Okay, I just went over some old stuff this week to prepare for the next vast vast, upcoming test. I came across a Logarithmic Equation book, well, it's more than 300 pages long, it covers most things from Exponential to Logarithm. :woot: I have read about 1/4 of it, and I was stuck...
  9. T

    Simplifying Logarithm Expressions with Unknown Variables

    Homework Statement Given that \log_{4n} 40\sqrt {3} = \log_{3n} 45 find n^3 Homework Equations Logarithm properties The Attempt at a Solution I can get an expression for n but looks messy, and suspect there is probably a more compact answer. This is what I did...
  10. P

    Intermediate algebra , Natural logarithm question

    Hello everyone, I do not understand how:: e raised to ln of x = x ? this notation might make more sense:: e^ln x=x ? Thanks for the help.
  11. B

    Natural Logarithm Manupulations

    Homework Statement xln(2x+1)-x+\frac{1}{2}ln(2x+1) = \frac{1}{2}(2x+1)ln(2x+1)-xHomework Equations ln(x^a) = aln(x), ln(xy) = ln(x) + ln(y), ln(\frac{x}{y}) = ln(x) - ln(y)The Attempt at a Solution I have no idea how you can go from xln(2x+1)-x+\frac{1}{2}ln(2x+1) to...
  12. D

    Finding the power using logarithm

    Actually, I am trying to use what I have learned on school to something else Homework Statement 3*10^x = 1.73*10^14 Homework Equations lga^x = xlga The Attempt at a Solution 10^x = (1.73 * 10^14)/3 10^x = 5.767 * 10^13 xlg10 = 13lg(57.67) x=13lg(57.67) x=22.89 :\...
  13. D

    Proving ln(z^alpha) = alpha ln(z) for Complex Numbers

    Homework Statement Show that ln(z^\alpha) = \alpha ln(z) where 'z' and 'alpha' are complex. Homework Equations ln \alpha = ln r + i(\theta + 2*n*\pi) The Attempt at a Solution For the left hand side I have ln (z^\alpha) = ln...
  14. Repetit

    Logarithm of numbers with units

    Hey! I have always learned that functions like logarithms, exponentials, trigonometrics etc. have to operatore on pure numbers and not numbers with units. For instance, you cannot write: Sin ( 5 kg*m/s^2 ) But in chemistry I often find formulas where logarithmes of numbers with units...
  15. I

    Natural Logarithm Derivative question

    Hi all, I'm a bit puzzled by one of my homework questions. I got an answer, but I have nothing to check it with and I'm not sure that my answer is correct. The question states that y=ln(ln(ln(x))), and asks for y'. This is what I've done, but it seems a bit too simple to me...
  16. T

    Proofs of Logarithms: Proving Equality of a and b

    Can't start: (log_{a}b)(log_{b}a) =1
  17. H

    Solve Logarithm Problem: log2 2x -log3 (3x-1) = 2, Find X

    log2 2x -log3 (3x-1) = 2, solve for x... you guys don't hv 2 solve the question for me, just guide me to the answer:smile:
  18. Q

    Complicated logarithm problemor at least i think it is

    I was doing some assignment i have to give in, for math, and came upon this exponential equation: (2^x+1) + (2^x+2) = (2^1-x) + (2^3-x) I thought, pfft, that's easy...so i did it, wrong answer, tried something else, wrong answer..tried another tactic, and i think you can guess what...
  19. M

    Help Understanding What a Logarithm IS

    I need help defining a logarithm. My book simply says: A logarithm is an exponent. This stumped me because I can't see how that is. I don't know what question to ask, but I might not be apprehending the relationship between an expo. function and a log. function.
  20. A

    To find logarithm of a complex number

    #2 Hi, Well can anyone tell me how to find the natural logarithm of a complex number p + iq. Also please tell me how to convert it into logarithm to the base 10. An external link to a webpage (where all the details are given) will be appreciated.
  21. fstam2

    How Does U-Substitution Prove the Equality of Two Logarithmic Integrals?

    Confused, but tried it this way: Use u-substitution to show that (for y a positive number and x>0) \int_{x}^{xy} \frac{1}{t} dt = \int_{1}^{y} \frac{1}{t} dt so, u=t and du=dt if x=1 t=xy u=y(1)=y t=x u=1 or u=1/t and du/ln [t] = dt if x=1 t=xy u=1/y t=x y=1 Thanks for...
  22. quasar987

    Determination of logarithm (complex)

    The question is this: Consider p(z) a polynomial and C a closed path containing all the zeroes of p in its interior. Compute \frac{1}{2\pi i}\int_C z\frac{p'(z)}{p(z)}dz The solution given by the manual starts by saying that \frac{p'(z)}{p(z)}=(log(p(z)))'. But there is no...
  23. D

    Find "n" Using Logarithm: Solve y=kx^n

    my physics teacher told us that for now well be solving the equation of a line such as y=kx^n by trial and error for finding "n" using the multiplicative change in 2 points i.e x_1,y_1,x_2,y_2. what we would do is for example 2 points (13,1) (6, 1.4): n=\frac{y_2}{y_1}=(\frac{x_2}{x_1})^n...
  24. M

    How Do You Solve 10log1019 in Logarithms?

    Hello sorry to post another so soon. This book is VERY hard to learn from... its not very good at explaining. The question says: Evaluate the following logarithm: 10log1019. It never showed me how to do it when there's a number in front of the log. What I got from the log 1019 is...
  25. G

    Can You Prove ln(e)/e > ln(pi)/pi Without Calculations?

    I haven't been able to prove: ln(e)/e > ln(pi)/pi without calculating any of the values. Help would be much appreciated.
  26. R

    Solving Logarithmic Equations: Tips and Troubleshooting | Roger's Math Help

    hi could anyone tell me where I went wrong ? simultaneously solve 2logbase2 y = logbase4 3 + logbase2 x 3^y = 9^x But for the top I get y = 3 root x and bottom I get y=3x so what's gone wrong ? thanks roger
  27. T

    Mastering Logarithms: Simplify with 2/log9 A - 1/log3 A = 3/log3 A

    I don't know how to show that: 2/log underscore9 A-1/log underscore3 A = 3/log underscore3 A
  28. D

    Natural logarithm of negative numbers

    I'm puzzled by... \ln \left( -\frac{1}{2} \right) = - \ln \left( 2 \right) + i \pi Why is this true? How can I possibly get this result? I know that \ln \left( \frac{1}{2} \right) = - \ln \left( 2 \right). Thank you so much
  29. K

    Is ln(-x) Defined for Negative Real Numbers?

    Is it true that that ln(-x) is defined for x \in R such that x < 0? - Kamataat
  30. Link

    How Do Logarithms Simplify Exponential Equations and Factor Polynomials?

    My book have a really crappy proof of how log a^x = x log a can be true. Can someone help me? Another question deals with an application of it which made me really confused: Factorise (4a^3) - (29 a^2) + 47a - 10 then solve (4*4^3x) - (29*4^2x) + 47*4^x - 10 = 0 I see...
  31. N

    Exploring the Relationship between Logarithms and Exponents

    Hey I am doing an investigation for logarithms, and I have a question. logx^n = nlogx. Based on previous knowledge of exponents, could someone please explain why this is true? Thanks.
  32. V

    Solve Logarithm Equation 7^2x - 5*7^x - 24 =0

    I need to solve 7^2x - 5*7^x - 24 =0. Am I on the right track by starting with 7^2x - 35^x - 24 = 0?
  33. G

    How to Use Different Logarithm Bases on a TI-86?

    I'm trying to use LOGs other than log base 10 and base e on my TI-86. Can I accomplish this like this?: log base a of b = (log base 10 of b) / (log base 10 of a) ? or is it: log base a of b = (ln b) / (ln a) ? Help needed ASAP. Thanks!
  34. K

    Logarithm Problems: Simplifying Expressions and Solving Equations

    I've just introduced myself to logarithms and have done most of the questions, but am having trouble with one or two of them: Q1: Find values of x for which: Log(to base 3)x - 2log(to base x)3 = 1. I have no idea where to start on this question. Q2: Solve: 25^x = 5^(x+1) -6. On...
  35. C

    How do you add or subtract bar numbers in logarithms?

    I have a small problem with logarithms. We have to solve physics and chemistry problems using only logs. And I don't know how to do the following - 1.2341 + bar2.4412 Well actually my question is how do you add or subtract bar numbers ? (It's the numbers with '-' on top) Rohit.
  36. nucleartear

    Gibbs Paradox: Exploring the Logarithm Correction

    What I have not seen in books about the Gibbs paradox is that it doesn't exist if we make the Gibbs correction at the logarithm of the Z function, not at the Z function itself, in that way: \ln Z_{i} - \ln N_{i} ! where N_{i} is the number of identical particles of class i, where there...
  37. MathematicalPhysicist

    Taking the logarithm of the euler product

    can some one explain to me how is taking the logarithm of euler product gives you -sum(p)[log(1-p^s)]+log(s-1)=log[(s-1)z(s)]? my question is coming after encoutering this equation in this text in page number 2...
  38. M

    What are Some Solutions to Common Logarithm Problems?

    log_10x-2=0 ... that's log base 10 (answer: 100) ln(x+5)=ln(x-1)-ln(x+1) (answer: no solution. but why?) log_4x-log_4(x-1)=1/2 (answer: 2)
  39. Loren Booda

    Why is e chosen as the natural base for logarithms?

    Their must be over a million definitions involving the constant "e". What I would like is a description of the natural logarithm in natural terms, not just saying "e is where e [inte] dx/x=1, etc." 1 In other words, why choose this function to define e, and how does it most...
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