







A problem with logarithms 
20190823 

Iriogbe pose la question : Find the value : if log3 (a6) =2b and log2 (a7) =3b Penny Nom lui répond. 





4^x=2^x+6 
20190405 

Olivia pose la question : How do you find the (b,n) if the solution of the equation 4^x=2^x+6 can be expressed at logb(n) where b and n are both prime numbers? Penny Nom lui répond. 





Double the number of pennies each week 
20190228 

Donald pose la question : If I save a penny a week,double it every week,How many weeks will it take to reach 1,000,000 dollars Penny Nom lui répond. 





y=lnx+(1+ln2)/2 and y=x^2 
20190128 

Mike pose la question : Prove that y=lnx+(1+ln2)/2 and y=x^2 touch each other.
The course is about logarithm and root functions... how should I solve this problem? Penny Nom lui répond. 





4444^4444 
20171210 

Sashi pose la question : 4444 to power of 4444=?
Please share the result with simplification. Penny Nom lui répond. 





The derivative of f(x)=2^x/x 
20171128 

Chhavi pose la question : f(x)=2^x/x.
Find f'(x). Penny Nom lui répond. 





3^2x5=27 
20161214 

danaja pose la question : solve for the following 3^2x5=27 Penny Nom lui répond. 





Find two values of x satisfying f(x)=1 where f(x)=sin(ln(x)) 
20160121 

Ruth pose la question : I'm trying to find two values of x satisfying f(x)=1 where f(x)=sin(ln(x)) Penny Nom lui répond. 





Manipulating an expression using logarithms 
20150518 

Katie pose la question : Solve x=At^be^ct for b in terms of c.
The e is Euler's number, not a letter or random placeholder. v
I've tried 2 methods on my calculator, and I am unsure as to why they give me different answers, and which one is correct.
For some reason, when placing a multiplication sign in between the A and the first t, I get a completely different answer. Why is this?
Also, which is the right answer for the question I have?
Thank you!
Katie :) Penny Nom lui répond. 





logbase4 (sin x) = 0.5 
20141026 

Susan pose la question : Solve for x: logbase4 (sin x) = 0.5 Penny Nom lui répond. 





Logarithms 
20140828 

effaryna pose la question : how logarithms is applied in everyday life? Penny Nom lui répond. 





Differentiate ln[x(2x4)^1/2] 
20140628 

Igwe pose la question : If y=In[x(2x4)^1/2],find dy/dx at x=3 Penny Nom lui répond. 





How do we use logarithms in our daily life 
20140601 

ss pose la question : how do we use logarithms in our dailylife Penny Nom lui répond. 





Evaluate log3 14 
20131117 

Tash pose la question : Use the Change of Base Formula and a calculator to evaluate the logarithm, correct to six decimal places. Use either natural or common logarithms.
log3 14 Penny Nom lui répond. 





4=(1+.08)^x 
20130615 

Samantha pose la question : I can't seem to understand how to solve for x when it is in power form, here is the equation:
4=(1+.08)^x Penny Nom lui répond. 





How do i write log_8(P) =7 in exponential form? 
20130414 

nancy pose la question : How do i write this in exponential form log8P =7 Penny Nom lui répond. 





Solve 8 logx > x 
20130219 

Fulvio pose la question : Hi, could you solve this equation in algebraic form:
8logx>x Harley Weston lui répond. 





What is the domain of f(x)=sin(ln(x))/ln(x)? 
20130206 

Behrooz pose la question : Hi, the following problem may be interesting:
What is the domain of f(x)=sin(ln(x))/ln(x)?
Be careful, domain is not obvious.
Best regards
Behrooz Penny Nom lui répond. 





The exponential form of log8=P 
20120425 

Kristina pose la question : what is the exponential form of log8=P Penny Nom lui répond. 





A log equation in exponential form 
20111111 

Sarah pose la question : Express the equation in Exponential form
log2 to the 16th power=4 Penny Nom lui répond. 





Uses of logarithms 
20111109 

BEA pose la question : what is the use of logarithmic functions in real life or daily life? Penny Nom lui répond. 





Exponential form 
20110518 

Kara pose la question : How do I write this in exponential form?
log 1/8 = 3 Penny Nom lui répond. 





ln(12 x) = 6 
20110303 

Carolyn pose la question : solve the equation
ln12x = 6
Thank you
Carolyn Penny Nom lui répond. 





Daily life example of logarithms 
20110204 

owais pose la question : what are the application or daily life example of logarithms? Harley Weston lui répond. 





Simplify the logarithmic expression 
20101202 

Adori pose la question : Use the properties of logarithms to simplify the logarithmic expression. Log(1/250) base 5 Penny Nom lui répond. 





An equation involving logarithms 
20100927 

mindy pose la question : Hi,
I am trying to find x, the equation is:
log_2(log x + 2 (log x)^(1/2) + 1)  2 log_4((log x)^(1/2) + 1) = 1
Thank you very much for your time. =) Harley Weston lui répond. 





y =  log(x) 
20100428 

Alex pose la question : y=  log(x), where y = 4.3
solve for x. Harley Weston lui répond. 





Log[f(x)] 
20100308 

sourabh pose la question : What is the number of solutions of the equation
9 x 2  18 x + 5 = 0 for x, such that the expression
log10[(x+1)(x+2)] exists? Harley Weston lui répond. 





Exponential form 
20090805 

motaz pose la question : Let x = log_2 1/8 Write the exponential form of the equation and solve the equation for x Stephen La Rocque lui répond. 





Log_7 (4X) = Log_14 X 
20090708 

Mukulu pose la question : Help me with this question because i tried my level best to get the right answer but i failed Log_7 (4X) = Log_14X Stephen La Rocque lui répond. 





(logx)squared + log (xcubed ) +2 =0 
20090519 

michael pose la question : Solve for x: (logx)squared + log (xcubed ) +2 =0 Penny Nom lui répond. 





A property that decreases in value every year by 10 percent 
20090307 

PEter pose la question : there is a competition problem where a cottage is worth 25000 years, but it decreases in value every year by 10 percent. Without a calculator, is there a way to find after how many years, the cottage will be worth 2500? (besides multiplying it out and besides logs) Stephen La Rocque lui répond. 





An inequality with logs 
20090306 

Indrajit pose la question : (x/10)^(logx  2)<100..........how to solve this one?? Stephen La Rocque lui répond. 





If 5 to the power of y = 625, what is y? 
20090302 

Charlene pose la question : If 5 to the power of y = 625, what is y? Penny Nom lui répond. 





A log base 2 problem 
20081126 

dave pose la question : solve for x
(log base 2 of x)  (log base 2 of (x2)) = 3 Penny Nom lui répond. 





How do you solve "logx^4=4? 
20081117 

Scott pose la question : How do you solve "logx^4=4"? Penny Nom lui répond. 





2^x = 1,000,000 
20080906 

Peter pose la question : How do I solve for "x" in the following equation: "2 to the power of x = 1,000,000" ? Penny Nom lui répond. 





Solve e^x + e^(x+1) = 250 
20080825 

Laura pose la question : "solve this equation correct to three decimals"
e^x + e^x+1= 250 Penny Nom lui répond. 





Write log_2 (1/8) = 3 in exponential form 
20080627 

Jaime pose la question : how do you write log2 (1/8) = 3 in exponential form?
the 1/8 is a fraction and the 2 is a base of 2 Penny Nom lui répond. 





limit x>0 (logxlog(x1)) 
20080522 

kritica pose la question : lt x>0 (logxlog(x1)) Harley Weston lui répond. 





Which is larger, 727464^512693 or 624610^518548? 
20080518 

Yahweh pose la question : Lets say I have two very large numbers in the form of a^b:
727464^512693 and 624610^518548
I want to calculate which number is larger, but its unreasonable to type these numbers into a spreadsheet to get an answer right away. How could I determine the larger or the two numbers efficiently? Stephen La Rocque lui répond. 





The inverse of a function 
20080503 

keith pose la question : please help me find the inverse of this function:
h(t) = 2 + 4 ln(15t) Stephen La Rocque lui répond. 





log2x+log(x+4)=1 
20080412 

ryan pose la question : solve the equation for x, log2x+log(x+4)=1 Penny Nom lui répond. 





1(1P)^75=0.05 
20080405 

Amy pose la question : 1(1P)^75=0.05 Stephen La Rocque and Penny Nom lui répond. 





ln (x)  x = ln (2) 
20071118 

James pose la question : How do you make x the subject of
ln (x)  x = ln (2) Stephen La Rocque lui répond. 





Logs and exponentials 
20070731 

Marsia pose la question : Explain how the functions of exponents and logarithms relate to each other. Penny Nom lui répond. 





log_{a} b + log_{b} a < 0 
20070708 

Claire pose la question : Suppose a, b are real numbers taking all positive values except 1, determine (without the use of calculators) whether there exists values of a and b such that log_{a} b + log_{b} a < 0 Penny Nom lui répond. 





log(0.81) 
20070628 

Ade pose la question : If log 3 = 0.477 . The answer of log 0.81 Harley Weston lui répond. 





Log base 2 of log base 2 of x 
20070627 

alex pose la question : y = log base 2 of lag base 2 of x
The slope of the tangent to the given curve at its xintercept is..? Harley Weston lui répond. 





Understanding log equations 
20070510 

Sean pose la question : The number, N, of people who have heard a rumor spread by mass media at time, t, in days is modelled by N (t) = a / 1+ be^ kt. If 50 people have heard the rumour initially and 300,000 people hear the rumour eventually, find a and b. If the rumour is initially spreading at the rate of 500 people per day, find k. Penny Nom lui répond. 





What is the limit of 3.x^(3/x) as x approaches +infinity? 
20070411 

Teodora pose la question : What is the limit of 3.x^3/x as x approaches +infinity ? Haley Ess lui répond. 





A logarithm of a product and the product of logarithms 
20070227 

Sharon pose la question : Can you please explain Explain the difference between a logarithm of a product and the product of logarithms and give examples of each? Stephen La Rocque and Penny Nom lui répond. 





A problem involving logs 
20061126 

Beth pose la question : any help would be appreciated on how to solve without using the change of base formula for logarithms in the solution and check of the solution!!!
log256 (x) + log16 (x) + log4 (x) + log 2 (x) = 7/4 Stephen La Rocque and Penny Nom lui répond. 





How many digits are in the number 2^64? 
20060614 

Trang pose la question : How many digits are in the number 2^{64}? Stephen La Rocque lui répond. 





An equation involving logarithms 
20060305 

Chris pose la question : Given that log_{e} y = 0.3log_{e}x+1.2 show that y=3.32 x^{0.3}
Penny Nom lui répond. 





6^(x+1) = 12^(x3) 
20060205 

BB pose la question : 6^{x+1} =12^{x3} Penny Nom lui répond. 





Differentiation, powers and logs 
20060106 

Claudia pose la question :
Question: how do I find the derivative of
x* ln(x+(e^2))^2
x^lnx
x^(e^(x^2))
Penny Nom lui répond. 





cos x * cos 2x * cos 4x * cos 8x 
20050829 

Leandro pose la question :
A = cos x * cos 2x * cos 4x * cos 8x
What's the value of log A at base 2?
Chris Fisher and Penny Nom lui répond. 





y = log(x) + x. Solve for x. 
20050826 

Alain pose la question :
I have the following equation:
y = ln(x) + x
How do I solve for x?
Penny Nom lui répond. 





Extraneous solutions 
20050204 

Heather pose la question : My teacher wants to know why there are extraneous solutions in logarithms? Penny Nom lui répond. 





Some logarithm problems 
20050127 

Jo pose la question : Given ln x=7.1; ln y=8.2, Find ln(x^3y^7) Penny Nom lui répond. 





ln(hx+n) 
20050107 

Anibal pose la question : if I have the eq.
y=hx+n
and I want to know ln(y), how do I process
ln(hx+n)? Penny Nom lui répond. 





Two problems 
20040802 

JJ pose la question : A question on my homework assignment about logs says "suppose that x=logA and y=logB & write the expression in terms of x and y"
log(A  B)
Is this even possible? It seems like a typo.
Another is: "solve for t."
12(1.221)^t = t + 3
Is this one possible? If it is, I cant figure it out. Penny Nom lui répond. 





12(1.221)^t = t + 3 
20040714 

Jay pose la question : This problem has me stumped since i cannot separate the t and the 3. Here it is:
12(1.221)^{t} = t + 3
It's on a logarithm worksheet, but how do i figure it out?! Harley Weston lui répond. 





(ln(50/x)) / (ln(40/x)) = a 
20040621 

Un eleve pose la question : (ln(50/x)) / (ln(40/x)) = a = constante
comment extraire la variable x ??? Claude Tardif lui répond. 





Logs 
20040229 

Sandy pose la question : find X
3/2logb41/2logb8+logb2=logbx
my book uses prop 7 to rewrite as
logb4raised3/2logb8raised2/3+logb2=logbx; then writes
logb8logb4+logb2=logbx how did it get here? Claude Tardif lui répond. 





A problem with logs 
20040222 

Caitlyn pose la question : problem: ln x + ln (x2) = 1
I can solve this on the calculator, but the book wants 1+ [(sqroot)1+e]. How can I get the e? Penny Nom lui répond. 





Logarithms 
20040201 

A student pose la question : Where did the word logarithmic come from? Where/whom did it originate? Harley Weston lui répond. 





Domain of a function 
20031014 

Karim pose la question : Find the Domain of the Function H(x) = Log3 (4x + 7)10 H(x) = log base 3 times 4X plus 7 minus 10 i am having problem solving these kinds of problems. Penny Nom lui répond. 





Applications of logarithms 
20030916 

A student pose la question : I have a project due in my algebra two class dealing with logs and where they are used in life, but I am having trouble finding websites that relate. So I would really appreciate it if you couldhelp me. Penny Nom lui répond. 





Natural logarithms 
20030722 

Amanda pose la question : I'm going into my senior year of high school. I will be taking AP calculus, and my teacher gave us some homework over the summer. However, there are two things that I do not understand how to do. The first is, she wants us to be able to generate a unit circle by hand using 30, 60 and 90 degree triangles. I have used the unit circle in trigonometry, however I was never taught how to draw it. Secondly, I need to know how to do natural logarithms without a calculator. I was not taught how to do this, and the worksheet I was given only showed me how to complete them using a calculator. Claude Tardif lui répond. 





1996^1999 and 1999^1996 
20010729 

Rajesh pose la question : what is greater 1999^{1997} or 1997^{1999}? Chris Fisher lui répond. 





Two log problems 
20010616 

A student pose la question : Hi..this is one of 9th grade student in Fort Worth TX. well..I am doing EPGY stuffs in my school right now..and.. me and my teacher had problems to solve some advanced logarithmic thing. so I searched some sites to solve these two questions  (log base 7 * 10) * (log base 10 * X ) = 2
 log base 10 * (3x4) + log base 12 * X
 (log base 12 * 2) + (log base 12 * 5)
= log base 10 *4 Harley Weston lui répond. 





An integration problem 
20001130 

A student pose la question : If a>0 and the integral from b to 0 of 1/(1+x) equals 1/2 the integral from a to 0 of 1/(1+x), express "b" in terms of "a" Claude tardif lui répond. 





Where will we use this in the real world? 
20001011 

Jane Ann Musgrove pose la question : As a teacher of mathematics, I am always asked "Where will we use this in the real world?". I am seeking ideas/sites via the internet where students can find answers to this type of question. Can you help me? To be more specific, right now I am interested in finding careers where the employees would use the concepts of "Radicals", "Matrices", and "Logarithms". This information will be used by students to make presentations to the class on their findings from internet searches. Harley Weston lui répond. 





Logs and trig functions 
20000912 

Becky pose la question : How do they get these answers?  log 8 + log 2 = ?
Answer is: log 16
 For 0 degree < x < 90 degree, how many solutions are there for the equation 2sin x = cos x?
Answer: 1
Penny Nom lui répond. 





Radioactive decay 
20000518 

Catherine Sullivan pose la question : Please help me with the following: The radioactive isotope carbon14 is present in small quantities in all life forms, and it is constantly replenished until the organism dies, after which it decays to carbon12 at a rate proportional to the amount of C14 present, with a half life of 5730 years. Suppose C(t) is the amount of C14 at time t.  Find the value of the constant k in the differential equation: C'=kC
 In 1988 3 teams of scientists found that the Shroud of Turin, which was reputed to be the burial cloth of Jesus, contained 91% of the amount of C14 contained in freshly made cloth of the same material. How old is the Shroud according to the data?
Harley Weston lui répond. 





Two calculus problems 
20000501 

Kaushal Shah pose la question : How Do WE Integrate the following Functions,  Integral xtanx dx
 How was natural base "e" discovered and why e=2.7.......
Claude Tardif lui répond. 





Logs 
20000412 

Jessica pose la question : Write as a single log 3ln x  2ln(y+e) + 5ln(x12)  4ln y Harley Weston lui répond. 





Characteristic of a logarithm 
20000314 

Andrew Strauss pose la question : What is the characteristic of log base 18 of 1980 ? Harley Weston lui répond. 





Logarithms 
20000118 

Jennifer pose la question :
Hi I have a test tomorrow and I was wondering if you could help me with these two problems. Explain how to express y in terms of x if log3y=4log3(2X) The LN key on your scientific calculator is not working, but the ex and LOG keys are. Write directions for calculating a natural logarithm using the ex and LOG keys. Explain why these directions will get you the right answer. Harley Weston lui répond. 





Logarithms 
19991216 

Pierre pose la question : Can you please answer those three question  inverse or the exponential function.
logx 81 = 4, x expo4 = 81, x = +or 4square root 81, x = +or 3 s.s = {3} Why is 3 not acceptable.  .
. . Harley Weston lui répond. 





Log Cancel 
19991203 

Justin Murray pose la question : Ok I feel like a goof because I know this and I cant think of an answer But I want to isolate the x in the function y=2^x how do I do this? Harley Weston lui répond. 





Two derivatives 
19991116 

Gina Renicker pose la question : The derivative of: y=e^{(xlnx)} and y=x^{2arctan(x1/2)} Harley Weston lui répond. 





Derivatives with logs 
19991026 

Kate pose la question : What is the derivative of 5 to the 5x2 at x equals 0.8? Harley Weston lui répond. 





log(a) 
19991022 

Brenda Miskimmin pose la question : I need to know the mercury concentration in mg/L or ng/L for the following: log M (Hg) = 8.5 where mw of Hg=200.59 (it's the negative sign in front of log that confuses me). Harley Weston lui répond. 





Solving using logs 
19991011 

Rich Bolton pose la question : Here's my question: $541.39(1+i)^{15}=784.09 Can you please show me how to do this? Penny Nom lui répond. 





A log problem 
19990508 

N. Lam pose la question : I don't understand how to do this type of question: log(base absolute value x)y = log(base abs.val.x)2 + log(base abs.val.x)(Cos x) How do you graph the equation also, if 2(3.14)<=x<=2(3.14) Harley Weston lui répond. 





John Napier and e 
19990206 

Shimin pose la question : I would like to ask about the exact definition of e, its history (like how John Napier came about discovering it) and its applications in problems and real life situations. Thank you! Chris Fisher lui répond. 





Logs 
19981021 

Benny pose la question : What does log means? How come we have to use log Chris Fisher lui répond. 





Two Problems 
19980728 

James Pulver pose la question : How do you solve these problem? If log abc=16 and log ac=12 , find b. (The logs are log base 10.) and If a and b are real numbers, i^2 = 1 and (a+b)+5i=9+ai what is the value of b? Jack LeSage lui répond. 





A Problem with Logs. 
19971126 

Herman pose la question : Given log 24=a, log 25=b and log 26=c, express log 39 in terms of a, b and c. Penny Nom lui répond. 





Natural Logarithm Functions 
19970423 

Rickson pose la question : The following two questions are some of my son's homework that he is having trouble with......any advice or assistance would be appreciated. (eX)5=1000.............the X and 5 are exponents lnx + ln(x+3) = ln10 In each question the problem is to find x. Harley Weston lui répond. 

