How can I get Logarithms?

Question

I used to be great at math.

It's my favorite subject but when I did Algebra 2 my sophomore year I barely passed with a 74. Mostly due to logarithms.

I understand when the teacher is explaining and giving examples but when it comes to the homework and tests it totally escapes me.

any ideas?

I'm in PreAP PreCal this year and logs are a big part of it I heard.

Answer 1

gurlfriend u gotta look at em logs and work IT. work IT gurl

You see 10^x =100?

You know its 2 but gurl you have to cancel the bases to get 10^x=10^2 giving you x = 2. Or you could bring down the logs and get xlog(10)=log(100) = x = log(100)/log(10) =2

You gotta be fierce cuz like Tyra Banks says " KISS MY FAT ***"

What happens when u at the mall shopping for change and u notice that there are 2^n-1 shoes and you got only 1000000 cents or 10,000 dollars? Gurl thats when u need some logarithims. Or u can just factor (10^3)^2 = (2^10)^2 = 2^20

So n-1 = 20, or n= 21 shoes. Gurl u gotta work it

Answer 2

Logarithms are just another way to write exponents.  Take, for example, the equation:

x^y = z

In log notation, this is (the capitalized ones are normal, the lower case x is subscript)

LOGxZ = Y

Basically, if you were to take LOGxZ, you're asking what power x needs to go to to get to z.  It's less intimidating than it seems.  So:

LOGx4 = 2

can be translated to

x^2 = 4

So x = 2

Make sense?

Answer 3

it'd be better if you could tell us what exactly you are having problems with, be a little more specific so we can explain the concept to you

Good luck :)

Answer 4

Basically logs are like this...

First a little typing definitions...

log10(x) = log base 10 of the number x.

What it's asking is 10 to the power of what number equals to x.

log10(1000) = 3  (because 10^3 = 1000)

log10(100) = 2  (because 10^2 = 100)

log10(10) = 1

log10(1) = 0  (yes, 10^0 = 1, I know it's strange, but true)

log10(1/10) = -1

log10(1/100) = -2

etc. etc.

the logs don't have to be base 10, they can be any base except 1 or 0.

Often we use the "natural log" (no, it's not a health food item)

it's abreviated Ln (usually L is lower case, but it's hard to see that here because of the font, lower case L looks like upper case i in this font.)

the natural log is log base e, e is just a number like pi.  It's about 2.718281828459....

There are many rules and tricks to using logs...

For example log(xy) = log(x) + log(y)

log(x^n) = n*log(x)  ...    * means multiply

log(x/y) = log(x) - log(y)

Log( 0 ) is undefined.

Log( -n ) is a complex number (has an imaginary part)

can't think of much else... takes a bit of practice to learn the rules, but once you do, logs are really pretty easy and I think you'll like them.  And, yes, they are useful!  In chemistry especially, but also in some physics and certainly engineering applications.  Decibals (sound intensity) is a log scale and so is the Richter scale (for earthquakes).

Take care,

David

www.tutor-homework.com

Answer 5

I was really never taught much about logarithms, I only know how to use the log rules in Calculus.  Tomorrow will be my first day in Calculus 3 and I can tell you I haven't had to know much about them, I'm not saying that I don't want to learn or that you shouldn't, but don't worry about it, if you are taking PreCal they will teach you anything you need to know.

Answer 6

log is invers av exponenshals...du yu understand exponeshals?