Skip to main content

Questions tagged [logarithms]

Questions related to real and complex logarithms.

2 votes
0 answers
22 views

Find the point of intersection of an annuity and an investment

We were completing some classwork for Annuities and finding the Sum of a G.P for simple situations as well as finding the time take for an annuity to reach a given value. Given the context we wanted ...
Daniel Beadle's user avatar
0 votes
1 answer
41 views

How to solve for a value in a log

I have a formula: Weight=onerepmax*(0.488 + 0.538 * ln(-0.075*reps)) And I need to solve for reps given a onerepmax and a weight. I got as far as: ...
RobKohr's user avatar
  • 113
0 votes
1 answer
46 views

Determining the witnesses (constants $C_0$ and $k_0$) when showing $(log_b n)^c$ is $O(n^d)$ (b > 1 and c,d are positive)

I'm having a hard time finding the constants/witnesses $C_0$ and $k_0$ that show $(\log_b n)^c$ is $O(n^d)$. That is $|(\log_b n)^c| \leq C_0|n^d|$ for $n > k_0$ (b > 1, and c,d are positive). I ...
Bob Marley's user avatar
-5 votes
2 answers
85 views

If the domain of $f(x)$ is $(-3, 1)$, then what is the domain of $f(\ln x)$? [closed]

I need a clear explanation for this question: If the domain of $f(x)$ is $(-3, 1)$ then the domain of $f(\ln x)$ is ... a) $\;(e^{-1}, e^3)$ b) $\;(0, \infty)$ c) $\;(1, \infty)$ d) $\;(e^{-3}, e^...
Rit Mukherjee 's user avatar
-1 votes
3 answers
87 views

Is there any other function than $log$ for which $f(ab) = f(a)+f(b)$ and $f$ is monotonic? [closed]

Is there any other function than $log_{x}$ for which $f(ab) = f(a)+f(b)$ and $f$ is monotonic? If the answer to this question is yes, how can I find such functions?
mmh's user avatar
  • 243
0 votes
6 answers
195 views

How would you prove $\log_{2}x < \sqrt x$ for $x > 16$? [closed]

I'm not really showing how to prove this, since I tried finding the $x$-intercepts/zeros of $f(x) = \sqrt x - \log_{2} x$ , and see that $x = 4, 16$ work but inspection, but I'm not sure how to ensure ...
Bob Marley's user avatar
-3 votes
2 answers
191 views

How do you solve this equation $ \log_{2}(x) = \sqrt x$? [closed]

Disclaimer: Guys before voting to get the question closed I strongly feel we should instead have a feature on MSE that can merge such similar/duplicate questions since we got some really cool/through ...
Bob Marley's user avatar
2 votes
1 answer
90 views

Solving $\frac{\ln(y/x)}{y-x} = t$ for $x$ [duplicate]

I am having trouble solving an algebra formula which is for a project of mine. I must solve for $x$ ($y$ is a known value). $$\frac{\ln\left(\dfrac{y}{x}\right)}{y-x} = t$$ As I try to solve the ...
user1343039's user avatar
-4 votes
0 answers
108 views

Find $\arcsin c$, $\, c\in\Bbb C$ [duplicate]

A math fan sent me a solution of the weird equation $\sin z=2$ posted in Quora. It is Weird because in real calculus, we experienced that $-1\leq \sin x\leq 1$. I saw this question in so many places ...
Bob Dobbs's user avatar
  • 11.9k
-2 votes
1 answer
52 views

Why is logarithm with base 10 having number greater than 1 always positive? [closed]

Consider logarithm with base 10 and number k Why will it always be positive if k>1 and negative if k<1?
Anvi Mahajan's user avatar
1 vote
2 answers
77 views

How to calculate the limit $\lim_{x \to 0}\frac{\ln(1 + \sin(12x))}{\ln(1+\sin(6x))}$ without L'Hôpital's rule?

$$ \lim_{x \to 0}\frac{\ln(1+\sin12x)}{\ln(1+\sin6x)} $$ I know it's possible to calculate this limit just by transforming it; I think you need to use the knowledge that $$ \lim_{x \to 0}\frac{\ln(1+x)...
Maciej Miecznik's user avatar
2 votes
2 answers
62 views

Why the property of exponents holds true even for fractional powers

How can we prove that the property of exponents a^m × a^n =a^(m+n) (where "^" this sign denotes the power a is raised to)holds true even if m, n and a are fractions? Like I can clearly see ...
Shyam's user avatar
  • 49
1 vote
2 answers
59 views

Unexpected asymptotic logarithm behavior

I have recently seen a rather confusing asymptotic property of logarithms: $$ \log(n^4 + n^3 + n^2) \leq O(\log(n^3 + n^2 + n)) $$ I find this very unintuitive. Why would the log of a bigger ...
CharComplexity's user avatar
1 vote
0 answers
66 views

Why the log function is so important on the plane?

I am studying right now some Complex Analysis and I have seen the importance of the (complex) logarithm function in almost every subject in it. Now I'm intrigued with that (possible) relation between $...
underfilho's user avatar
0 votes
0 answers
46 views

When Does ((n^a)-1)/a)) Equal e; A Sophomore's plight

I am a high school student (sophomore) and have come across something I would like explained. I was watching 3blue1brown for an explanation of calculus, when he used the formula: lim a->0 (d/dx(n^x)...
Andrew Thorson's user avatar

15 30 50 per page