Showing posts with label Logarithms. Show all posts
Showing posts with label Logarithms. Show all posts

Friday, January 24, 2014

Sunday, December 8, 2013

log5(12). How would you do it on the calculator?

Use log base conversion...check your textbook for details...
log(12)/log(5)=ln(12)/ln(5)=1.543...

Saturday, November 30, 2013


find the value of x
log3 x = 4

Your Answer:
log3+x+=+4
the inverse to

log3%28x%29 is +3%5Ex

so we raise both sides of the equation to 3
3%5E%28log3+x%29+=+3%5E4

x=81 

Saturday, November 23, 2013

What is the logaritmic form of the equation 3^x= 12

We will use the inverse property of logs to help us 

3%5Ex=+12 

has a base of 3 so we use log base 3 which we'll denote by 

log3 

log3%283%5Ex%29=log3%2812%29 

log3%2812%29=x 


:)

Wednesday, October 16, 2013

how do i do this: 1 /loga(abc) +1 /logb(abc) +1 /logc(abc) ?

use the change of base identity: 
1 /loga(abc) +1 /logb(abc) +1 /logc(abc)=
(log(a)+log(b)+log(c))/log(abc)

Saturday, August 10, 2013

How do you find 10^(1/10) without a calculator?

Solving this problem by hand could be a formidable task depending upon the method of solution. Let's assume we are only restricted from directly using a calculator and we are allowed to use tables, and we can check our progress with a calculator. Furthermore we'll assume that we want a relatively easy way to do this, but we are willing to need to do a lot of handwork. First we do some algebra:
















Next we consult logarithm tables by searching for what value of log(x) is closest to 0.1. A careful search puts us between 1.25 and 1.26. That is to say: log(1.25)=0.09691 and log(1.26)=0.1003705

Averaging these two results yields: log(1.255)=0.09864025. The actual value is log(1.255)=0.0986437258, so that's not too bad!

From this we deduce that 0.09864025 < log(x) < 0.1003705, which tells us that log(1.255) < log(x) < log(1.26).

By repeating this process we can muddle our way to a decent approximation.

The value is not rational but here are 20 decimals: log(x)=1.2589254117941672104