Category Archives: maths

Logarithm

Enough is enough, ever since i started doing some efforts in maths, i seem to be having some quite good enough success with it, but unfortunately as most of you all know i kind of always escaped classes when i was in sc or hsc, [specially when they were working on logs] so here after trying to learn a bit about it, here’s something that hopefully might help others.

real life logs nothing to do with the maths one
real life logs nothing to do with the maths one

so let’s get this done…

we shall start by taking an example…

23=8, (in words we say two to the power of 3 equals 8, 2x2x2=8).

in log terms we will say..

log28=3 , (in words we shall say the logarithm to the base 2 of 8 is 3)

that is, 2 to the power of WHAT will be 8? hence in this case it is 3. [You may use your calculator to verify that 23 is infact 8]

so the general form is

ab = c and logac=b

now let’s get some practice:

1.) Find the Value of log525 ?

Now, most people who [like me] never went to those log maths class or who have been sleeping like a log when they were in that class would try hard as hell to try to figure out how the heck to change the base of log in their calculator so as they can computer it directly on their calculators, but heh, don’t tire yourself, most probably there isn’t [atleast in the calculators that you are allowed to bring in exams]

there are only two things log related in the calculators, log, which is base 10, and ln which is base e, we’ll use log.

SO,

back to the question, basically we are asking 5 to the power of WHAT gives 25??

  • [step1.] place it in the form ab = c

we are given log525, in the form logac=b, it will be log525=b, hence the unknown here is b

a=5, c=25, b=?

5b=25

  • Solve the equation 5b=25

5b=25

b log 5 = log 25

b=(log 25) / (log 5)      [use calculator]

b=2

et voila! we got the answer.

Simple isn’t it? [i really wonder why i really hated that then] … probably coz i always found alternatives

With that you shall be able to solve any logarithm related equations, just find and replace. Till then, good luck and well, feel free to comment and add suffs, that’s how it works, coz am sure there;s a lot more to that. My next post will probably be on jacobi’s convergence or solving recurrence relations :p.

http://www.blogged4ever.com/2008/09/19/logarithm/

+$3|v3n

[note i still hate maths because i don’t find it useful and soo illogical while programming is soo natural and soo logical] :D

ps. lemme know in case of errors.

Forthcoming maths series

Hello people, as you most probably know i am reknowned to be very bad at maths [worldwide], i was almost beginning to believe that i was dumb, but then something changed, i realized that one can work ok in maths if we put lots of efforts [ ohh hell yes ], am normally the sort of dude who is lazy lazy lazy, since i am used to most of the things that we do in computer science and stuff, i usually never had any problems with most of the subjects, since i just had start reading on the eve of the exams [which is something i won’t recommend]. Anyways, for my own sake and for the sake of many others who are like me, i hope i’ll be able to write a few series of notes that will help me and hopefully others like me to try to understand how to work out those problems…

note. most probably i am not going to be able to explain the “whys” but tleast i’ll try making it clear about the “hows”… while i always like to know the “whys” of things… i am on a race against time, i check the “whys” only at night, so if you find something that you feel you can explain, you are welcomed to comment [and who knows if i am free i’ll copy add your explanation and credit you on it].

Hope we’ll have some fun with maths.

ps. don’t laugh, i need to make this effort to teach myself :p

+$3|v3n