Take the 2-minute tour ×
Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

I am looking at logarithmic functions, and, lets say, log2 (x+3) is having a bit of a growth rate between 0-10 values of x, but then it has almost no growth rate.

I need some function that looks similar to a linear function, but is slightly bent like a logarithm function is.

How do I modify my logarith function?

Edit: I made something like this: http://www.wolframalpha.com/input/?i=graph+log_100%28x%5E128%29++from+x%3D2+to+x%3D4000 and I have almost the results I want, but I would like this function to not go as extreme high in first 0-500 values of x axis.

share|improve this question
    
You are aware that $\log x^{128} = 128\log x$, so the function you've linked is just some scaled version of $\log x$? –  martini Sep 26 '13 at 14:51
    
@martini: Wasn't aware, of that, thanks. ;) But I need to modify it somehow so it will get "wider" at the beginning, and I don't know how to do that. –  ojek Sep 26 '13 at 14:57
add comment

1 Answer

up vote 2 down vote accepted

Modification: $$a-a^{1-\frac{x}{b}}.$$

This starts at the origin, and quickly converges to $a$. After a point there is relatively speaking little growth. Try making $a=10$, and $b=5$, and then setting your aspect ratio to 1 in a better grapher (for example ojek graph allows manipulate constructions).

share|improve this answer
    
Ouch. wolframalpha.com/input/… did I input it right? I am looking for something that will look more or less like a north-west quarter of a circle that starts in 0,0 –  ojek Sep 26 '13 at 15:32
    
@ojek See my modification. I made a manipulator with square aspect ratio in ojek graph –  J. W. Perry Sep 26 '13 at 16:19
    
Thank you, that helped. :) –  ojek Sep 26 '13 at 16:41
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.