# How to Solve Logs on the Texas Instruments TI-30X iis Calculator

Hello and welcome to HP Calc I’m Rick
and today we’re gonna look at how to find logs on the Texas Instruments TI 30
X ii s calculator. To do this we’ll be using the log key located here and the
LN or natural log key located here. Now in this calculator the default log base
is a log base 10 so if we wanted to find a number that was log base 10 we would
simply press the log and then enter the number we want to find the log of. So if
we wanted to find log base 10 of 100 we would go log 100 equals 2, easy enough. We can do
something similar with the natural log if we wanted to find the natural log of
a number so okay in this example 100 you press the LN key enter the 100 and press
equals and we get the natural log of the number, but what if we wanted to find a
log base that isn’t 10 or natural log? To do that we can use something called the
change of base formula which means we divide the log of the number we’re
trying to find by the log of the base we’re trying to use. So for example if we
wanted to find log base 2 of 100 we would follow, this we would enter log of
100 divided by log 2 equals and this gives us the answer of log base 2 of 100
which is 6.643856 etc. All right I hope this helps and good luck on
those tests

## 13 thoughts to “How to Solve Logs on the Texas Instruments TI-30X iis Calculator”

1. Bruce Russell says:

Thanks man really helpful!

2. Hakimi Zohal says:

THANK YOU! This was really helpful!

3. SNIGDHA ROY says:

This was really Helpful 😊

4. Jake Walker says:

thanks so much!

5. Scythe 12 says:

Thank you for helping me out👍🏽

6. MTutoriales#2018情報 says:

Thank you so much sir! I was breaking my mind in class trying to find out how to write the base in the calculator.

7. MagniMusicLover says:

Thank you very much for this!

8. Colonel Mustard says:

You da man

9. Scratch Pad says:

+HP Calcs Thank heaven I have found your video again! Last semester at Salt Lake Community College (Fall 2018), I was in Math 0980 and they had a unit (I forget which module it was in) where we needed to find logarithms. Luckily, as I remember, most of the logs were base 10 and natural logs, but there were a few where we needed to find a different base. This semester (Spring 2019), Math 1010 has a unit in Module 8.3 where we are revisiting this.

10. Alex Madera says:

love how straight to the point you are

11. Xerxes Q says:

but WHY

12. Tahrin Choudhury says:

Can i use this calculator to solve Entropy calculation -2/5 log2(9/14)? Decision Tree problems. Can you please help how to use if this calculator has the key?

13. Kelly Tush says:

wow i'm actually so stupid. I've been trying to find the log key for a week now not realizing that its right in front of my face.