Log Definition and 632 Threads

Homework Statement A round wooden log with a diameter of 83 cm floats with 72% of its radius out of the water. What is the log's density? answer unit is kg/m3 Homework Equations density of water= 1000 kg/m^3 The Attempt at a Solution I've tried to find the area that is exposed, but...

Having some trouble understanding derivatives including numbers to the "X" power. For example, f(x)= 7^8^x, f'(x)=? help please!

Natural Numbers - Pi, Log, ... Greetings, I'm far from an expert on math and I wanted to appeal to smarter minds to help compile a list of numbers with non-repeating chaotic decimals: Here's the first 2 (the only 2 I can think of) Pi e I'd also include the order of prime numbers...

Hello everyone. I'm stuck on this problem and not sure how to apply the Unique factorization therem also called (Fundamental Theorem of Arithmetic). Heres the problem: http://suprfile.com/src/1/45ym0fx/lastscan.jpg The back of the book gives a pretty big hint which is the following...

Hi, In his notes, our teacher makes this approximation: \log(1 + 3e^{-2\frac{E_o}{\tau}}) \approx \log(3e^{-2\frac{E_o}{\tau}}) For \tau << E_o Also, and I don't think this matters, the logs are assumed to be natural logs. I was wondering what the justification for this was...

find the solution(s) to 2e^2x = e^x its on a practise exam I am doing. i did with my calculator, but how could this be done without a calculator?

Here are some log questions that I don't really have any idea how to do. I'd appreciate any hints/help... (solve for x in all questions) 1. 2^x + 4^x = 8^x All I could think of doing was converting them to the same base. I don't see how to simplify the left side of the equation so I can...

A boat floats across this river, and back, It takes 5 hours for it to reach point B, from point A, and then 7 hours to return to point to point A from point B. Naturally it's because not because the crew got tired on the way back, but because the flow of the river, or it's angle which is...

A log weighs 800N and has its center of gravity at the midpoint. Find the lowest coefficient of static friction necessary to keep the log from slipping. Answer (1.01) http://img115.imageshack.us/img115/8407/physicsproblem3ox.th.png Ok, so, i started out by finding my torque and force...

Find the first derivitive. Simplify if possible (factor). \begin{array}{l} y = x^{e^x } \\ \\ \ln y = \ln x^{e^x } \\ \\ \ln y = e^x \ln x \\ \end{array} There's a similar problem in my class notes where it was solved by taking the natural log of both sides. Is this...

Hey Integral, Did I log off my PF account on your computer?

I graphed y=logx+log2x and y=log2x^2 and the graphs came out a lot different. However when you simplify y=logx+log2x you actually get y=log2x^2! Any ideas about why the graphs are so different yet the equations are pretty much the same? thanx

Here is a problem that I was presented in my math class using logs and my entire group is stumped: Peter deposits $800 into an investment fund that earns 8% per year, compounded annually. Mary Jane deposits $1000 into an investment fund that earns 6% per year, compounded annually? When will...

this problem is an excerpt from an explanation of a time wieghted performance method. I feel that if I can follow this part the rest of it will make sense. now i know the answer is .1259 but I'm a little fuzzy on how exactly they got that, and their 'step by step' seems to miss some steps. it...

I am stuck on finding the solution to this problem. 2lnX = 2 + ln(X-1) Please show all steps for the solution. Thank you.

I'm working through an example problem wherein this bound is used: \left| \log \left( 1-\frac{1}{L^s}\right) \right| \leq L^{-\sigma}, where s:=\sigma +it and it is known that \sigma >1. How do I prove this? Should I assume the principle brach is taken?

Hi, I just need a little help in getting some sums. Can anyone of you give me a site where I can find sums in Log so that I can do them and practice a lot. I mean like sums in this type Show that log(xy)base16 = 1/2log(X)base4 + 1/2log(Y)base4 Thanks just need some sums of this type...

I'm taking cal 2 right now and i missed the part in cal 1 where he talked about "log theorem". Now this guy tells us that he's lazy when he corrects exams and if we don't use the log theorem to derive a term then he won't correct that term. I've looked on the net but couldn't find explanation or...

Hi, I am just a little confused with this log law of change base. Is there anyone who can give me a clear description with an example?:smile: Thanks

Hello everyone the problem I am messing up is: . Solve the following initial value problem: http://img59.imageshack.us/img59/9037/lastscan4vl.jpg When pluggin in answers and using my calculator to evaluate, its saying NON-REAL numbers, I'm messing up hardcore somewhere but not sure where...

Problem states: (A) Use mathematical induction to prove that for x\geq0 and any positive integer n. e^x\geq1+x+\frac{x^2}{2!}+...+\frac{x^n}{n!} (B) Use part (A) to show that e>2.7. (C) Use part (A) to show that \lim_{x\rightarrow\infty} \frac{e^x}{x^k} =...

If 3150g of a radioactive substance decays to 450g in 73 weeks, determine the half life of the substance to the nearest week. Solve algebraically using logarithms. 450=3150(x)^73 450/3150=x^73 73sqrt(450/3150)=x Now, the only problem is the answer says it is 26 weeks. Any help is much...

I have a tricky natural log in front of me. It's ln(1/x). The reason it's tricky is because I thought that I could re-write it as ln(1)-ln(x), as per the rules of logs, but that doesn't seem to agree with my calculator. Is there a reason why? Thanks!

http://img228.imageshack.us/img228/1799/untitled8av.png Kinda Tricky

I spent all of yesrterday going over a set of puzzles. One of them was: Assume you have a container divided into two equal sections (one on the left and one on the right). One section is filled with water and the other with air. A log is placed a long the divider between these two sections...

Ok, I worked this derivative problem, but my book has a different answer than what I got. I'm not sure why. I need to compute the derivative of log base3 of (x^3 + 2x) I came out with: 1/((x^3 + 2x)ln3) The book says that the answer is the same as mine except the numerator has a...

Hi i want to know if the log(10)(A/Ao)^10 gives 10*logA/Ao or 1 or 0

Hi all. I'm slightly confused with the following limit prob: \lim_{x\rightarrow \infty} \frac{(ln (x))^n}{x} which I know = 0. (n is a positive integer) It looks like it's of indeterminate form, that is \frac{\infty}{\infty} Using L'Hopital's, it looks like you get another indeterminate form...

What power must a man expend on a 100-kg log that he is dragging down a hillside at a speed of 0.50 m/s ? The hillside makes an angle of 20 degrees with the horizontal and the coefficient of friction is 0.9 m = 100kg v = 0.50 m/s \theta = 20 degrees \mu = 0.9 From here I thought that...

Graph Y1 = log (X^26) & Y2 = 26 Log (X) Are they Equivalent ? I drew the graph using X values ( -5, -4, -3, ... , 4, 5 ) and I got graphs, but don't know how to account for any differences in two functions.. Can anyone in here help

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oops wrong forum! Please move this thread...Q.1 Express in terms of the stated variable. If a = log (2) and b = log (3), what is log (25/9) in terms of a and b ? My work log (25) - log (9) = 2[log (5) - log (3)] And I don't know where to go from here. I tried a few different approach but can't...

I've been looking through my textbook for a question even remotly similar and no luck, if you could get me started witht this question I'd love to do it and then I'll write what I got and write it here. If y=x^2(a+z) determine an expression equal to log x. (Hint: you will need to take the...

Hey, here is a question I couldn't figure out. I think it's actually really easy, but the wording confuses me. A recent survey showed that the population, P, of Victoria is growing at an annual rate of 1.1%. Let P0 represent the population on January 1, 2001 and let t represent the time, in...

when trying to solve ln(x+4)=2 i tried this ln(x+4)=2 e^2=(x+4) ln e^2=ln(x+4) 2=ln(x+4) and round and round i go... where do i start to go wrong?

I have a class where I'm using the log function a lot, I would like to program a hot key to display log on my ti-89 for I don't have to mess with the catalog, any suggestions? Thanks Philip

Hello all. I am stuck on this homework problem. It wants me to find \frac {d^2y} {dx^2} when y= ln x^8 The book answer is \frac {-8}{x^2} But I only can get \frac {-8}{x^9)} Please give me some guidance Thanks

Whats the difference between log and ln?

Using log differentiation, find dy/dx, in terms of x for the following: y = (cosx)^sinx any help wud be appreciated, I am unsure of how to start this question, thanks in advance

How Do I Find The Logarithmic Expansions Of Log[x],i Mean The Series Of Log[x].it Is Urgent

This question should be easy to most people here and need some help on this question. 3log25 - log34 + log2(log39) My answer to this question is: = 3log25 - log34 + log2(log9/log3) = log2125 - log34 + log22 = log2125 - log34 + 1 = (log125 / log2) - (log4 / log3) + 1 = 6.703924778...

I can log on to any .tk website except for the main one http://www.dot.tk any help here?

Maths urgent help If there is a cubic log with a mass "M" and edges which have a length "2a" and is kept on top of a table,and there is a hole dug inside it right in between two parraral faces of this cube. This hole starts from the middle of one top edge(A) and leads on to the bottom of the...

hi guys, I am new to forums and need help cause I am doing engineering 1st year, and I am horrible at maths and chemistry (bad match :confused: ) equation is simple, x^2 Log x = 1, i have no idea wat to do with the 1 i turned it into x^2 log x -1 = 0 and then used y'=uv' + vu' and...

Help me solve for x in detail please: 8^x+13^x=108 Simply done graphically, but algebraically?

Can some one check my answers please? The answers are in my reply post at the bottom of this page THANKS :smile: I have a couple more log questions I am stuck on. They keep giving me log questions that they never showed me how to do.. very fustrating! I need to evaluate the following...

A while back in the school-year we were doing logs, and logarithm. We learned the power law, and such. It really annoys me when my teacher just throws something on the board like log and then shows us laws to remember. I don't even know what log is. Does it stand for a number? or is it just...

Ok so i was doing a problem involving finding the pressure of mercury at its boiling point (630.05K) using Troutons rule and the final answer seems a bit strange to me. Integration of the Clausius-Clapeyron Equation: {ln(\frac{{P}_{2}}{{P}_{1}}) =...

I have been working on this problem for a while. I am supposed to prove that log 2 = \lim_{n \rightarrow \infty} \frac{1}{n+1} + \frac{1}{n+2} + ... + \frac{1}{2^n}. The problem is that I have a hard time figuring out how I am supposed to prove that something is equal to a transcendental...

This is a quick graphing question. We have to graph Vout/Vin versus the log of frequency. Now the Vout/Vin would have no units but what about the log of frequency? Is it hertz or is it also unitless?