logs

  1. B

    divide two numbers using log table?

    How do you divide 3533 by 9043 using log table?
  2. H

    Log Simplification

    ok I hate logs so how would I simplify: z= 3- 3 log(x+y) thank you :D
  3. A

    Radical equation to be solved without logs

    Can anyone help me with this please
  4. A

    Natural Logs with e

    Hi. I am trying to solve for Si2 in this equation. = 0.0175 = 0.0255 I think I can use the log rule Log (ab) = Log(a) + Log(b) but I am not sure because of the (e -1)+1 portion. Help with the operational steps to solving for Si2 would be useful. I was not sure if I should post here or to...
  5. E

    Logs

    Please can you help me with an expression to solve the following problem: The half-life of a substance is the time it takes for the substance to reduce to half its original mass. Find the half-life of a 10kg rock if its mass reduces by 1% a year. Thanks
  6. Mr Rayon

    Partial derivative of natural logs

    Find the partial derivatives of the following function: Q=(1/3)logeL+(2/3)logeK Any help would be much appreciated! Below is my working out so far: \frac{\partial Q}{\partial L}= \frac{\frac{1}{3}}{L} \frac{\partial Q}{\partial K}= \frac{\frac{2}{3}}{L} Are all these correct?
  7. T

    Logs and a few other things..

    Hello, missed alot of my classes from being out of town due to a family emergency so im seeking help on a few questions. how do I solve: 1) log(1-x)-log(1+x)=2 ? 2) Use the population function to find the following - N(t)=5.4e^0.013t where n(t)=millions of people t=years since 1995 - What is...
  8. M

    Natural logs and solving for X

    I have to following problem but it seems the answer I have does not seem correct, can someone verify and perhaps point me to any potential issues ? Thank you. 3y + ln(x) = 2 ln(4y-1) I will just do each step I did to get my answer. 3y + ln(x) = ln(4y-1)^2 3y + ln(x) = ln(16y^2+1) ln(x) =...
  9. A

    logs and inverses

    Hi; The log and the exponent at the end are inverses to one another? if so why are x and y not reversed? y = -log3(x – 1) + 2 y – 2 = -log3(x – 1) -y + 2 = log3(x – 1) 3-y + 2 = x – 1 3-y + 2 + 1 = x. Thanks.
  10. A

    Differential of an integral of logs

    Hi, In the snippet below, I don't see how the complete transition is made from Equation 2.13 to 2.14. I can see where the first two terms come from in 2.14 - they're just the logs from 2.13 which have been separated. I can't see where the last term of 2.14 has come from, and the differential...
  11. C

    Simplifying logs

    Hello Guys, I am wondering if this is correct Given: Simplify: (log 5(base9) ( log 81 (base5) I expanded the logs and added them log 5 base 9 + log 81 base 5 I changed the base of of log 81 base 5 to (log 81 base 9)/(log 5 base 9) now i have log 5(base 9 ) + 2 / log 5(base 9) do the log 5...
  12. M

    Shannons and Nyquist/ logs

    hey....i want a way in which this equation can be simplified im trying to make (snr) the subject of the formula C = B * log (1 + snr) where b=2 and C=8 and also make M the subject of the formula C = 2B* log2 (M) thanks
  13. D

    inequalities and exponents

    Hi all, I'm trying to find the interval for this inequality: 2^x<x^2 Obviously the x-squared portion is easy. So I've got 2^x=x^2 Can you go xlog2 = 2logx?
  14. D

    Logarithmic equation

    I'm trying to solve: e^2x - 2e^x I tried e^xx = 2e^x divide by e^x ^x = 2 ln^x = ln2 (the answer is x=ln2), but the way i have the x "raised" on the left hand side is wrong, I think. Any hints?
  15. M

    Logs Simplify

    What does this simplify down to.. Im supposed to plot it against the log of time, not sure why this double natural log comes into play log(-log(S(t)))
  16. C

    simplifying logs

    log7(x-sqrt(x2-21))+log7(x+sqrt(x2-21)) i tried multiplying but i keep getting different answers :(
  17. A

    the value of b in logs

    Hi;Having problem with the b value in logs y = 3log[base 2](2x - 2) - 4(here I divide x by 2 and h by 2) y = 3log[base2]2(x - 1) - 4( here I divide x by 2 and leave h alone) Don't understand why?Thanks.
  18. Z

    A question about graphing natural logs

    Hi all! I'm new to the forums. I'm finishing up high school calculus and was looking for some help with a question. I was asked to find the regions of increase and decrease for y=xln(x^2) First, I found the derivative to be 2(1+lnx) Next, to find when the function is increasing, I had to solve...
  19. N

    Multiplication and Subtraction of logs with different bases.

    \text{If }a=\log_{12} 18, b=\log_{24}54\text{, then find the value of }ab+5(a-b) I am trying in different ways to equalize the bases. But I can't do anything as the bases are unequal.
  20. B

    Few questions about LOGS

    Hey forum, I'm a bit confused on a few questions, if the work is too hard to display just the answer would be alright I could work backwards to see what i did wrong! Thanks in advance! 1) comparing Log(base9) X -> 3Log(Base9)[3(x+6)]-6 explain what has happened to the graph. 2) Solve...