Question about Texas Instruments TI-30XA Calculator

1 Answer

I am trying to figure out how to enter negative logs into the TI-30XA. I have a chemistry exam on Tuesday and we need to be able to do problems with the negative log and I can't seem to find any information on it. A sample question is as follows: -log (2 x 10 (neg. 3 exponent)

Posted by on

1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    One Above All:

    The expert with highest point at the last day of the past 12 weeks.

    Top Expert:

    An expert who has finished #1 on the weekly Top 10 Fixya Experts Leaderboard.


    An expert that got 20 achievements.

  • Texas Instru... Master
  • 102,366 Answers

Use the +- key to the right of the decimal point to enter negative values and to change the sign of an existing value. For your sample:
2 EE +- 3 LOG +- =

Posted on Nov 15, 2010

  • narizacollin Nov 18, 2010

    I was using -log and was getting Error. Finally I entered my numbers first then tried the - log and it worked. Thank you so much!


1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

2 Answers

How to fix error mesage on TI-30Xa. Every time I press LOG an error sign comes up. how do i fix this?

To take the log of a number, enter the number then press the LOG button, then the =. To take the log of a negative number, enter the negative number using the +/- key just to the right of the decimal point. To calculate the negative of a log, calculate the log and then negate it using +/-. To calculate the antilog (inverse logarithm), press 2nd then LOG.

Bear in mind that LOG is the common (base-10) logarithm. For the natural (base-e) logarithm, use the LN key to its right.

Nov 07, 2011 | Texas Instruments TI-30XA Calculator

1 Answer

How do i find the negative log on a TI-30Xa


Ex: calculate -log(15.32)
  1. Calculate the log 15.32 [LOG] [=] result 1.185258765
  2. Then press the change sign key (-) result -1.185258765
You can also try 15.32 [LOG] (-) [=]. Try to veriufy it on your calculator.

Here is a picture of the change signd677d4e.jpg
Hope it helps

Dec 13, 2009 | Texas Instruments TI-30XA Calculator

1 Answer

How to use antilog?


As you well know the pH is the negative of the log in base 10 of the H+/H3O+ ion concentration. If we use [H+] to represent that concentration, then pH=-log[H+].
To obtain the [H+] you need to calculate the antilog. You write the definition in the form log[H+] =-pH and then calculate 10 to the power of each member. The equality remains valid as both members are treated similarly. Thus
10^( log[H+] ) = 10^(-pH)
Since raising 10 to a power is the inverse function of taking the log in base 10, 10^(log(x))=log(10^(x)) = x (they are inverse of one another), you are left with


Your calculator has a function [10 to x] accessed by pressing the [2nd] function key. To use it you must enter the negative value of the pH, press the [2nd] function key then the [10 to x], then the = key to get the result (concentration)
Exemple: let the pH=5.5, what is the H+ concentration?
With [(-)] being the change sign key, then
[H+]:[ (-) ] 5.5 [2nd][10 to x] [=]
The result is 0.000003162 or 3.16 x 10^(-6)

Hope it helps.

Dec 07, 2009 | Texas Instruments TI-30XA Calculator

2 Answers

Find the antilog on the TI-84 Plus for finding pH in chemistry problems

I'm not specifically familiar with the TI83 or TI84 but I've used a lot of TI calculators in my time, so I'll give it a try. If your trying to find the antilog of a number in base 10 enter the number and hit the (10 to the X) button. If you're trying to find the antilog of a number in in base e (natural log), enter the number and hit the (e to the X) button.

May 29, 2009 | Texas Instruments TI-83 Plus Calculator

3 Answers

Hoe do you use logarithm on TI-36X SOLAR?

Basically you first have to put your answer into scientific notation by pressing the 3rd key then the 6 key. The screen display should change to one big zero and two small zeros.

I was workinggon the same problem with a -log of a chemistry problem to get pH and I knew the answer because I calculated it on it TI-85, but we are not allowed to use graphing calulators on the exam (:-((() so I had to figure out how to do it on this one!

For example, I had pH =-log(2.828947x10^4)

On the TI-36X you change to scientific notation using the instructions above. Once the three zeros enter on the screen:

1^-04 should appear on screen, then you multiply by 2.828947

then your screen will show the answer in scientific notation.

2.828947 in big numbers and in small numbers -04
From there you simply press:
and your answer will show up as a negative number. Just take the absolute value of that and you have your answer. Took me like 30 minutes the night before a huge chemistry exam to figure that out! Hope it helps someone!

May 09, 2009 | Texas Instruments TI-36 X Solar Calculator

3 Answers

Find the antilog on the TI-83 Plus for finding pH in chemistry problems

I reccently had the same problem, but I have a Ti-84 Plus,and I am disgusted by how poorly this matter is covered by Texas Intruments. Esp. since the solution is rather simple.

The antilog key is [2nd] [log] or the 10^x. On your screen it should apear as 10^( and then you just input the value that you want to find the antilog of.

When used to solve pH problems remember to input the pH value as a negative number, since pH= -log[H+] then [H+]= antilog(-pH).

Hope that helped))))) ^^

May 10, 2008 | Texas Instruments TI-83 Plus Calculator

1 Answer

Chemistry problem

You enter a pH value and change the sign to minus, then hit 2nd LOG which is 10^x. The x value is what you're looking for. To put the answer in scientific notation, press 2nd 5 to do so.


For a pH = 4.1

-4.1 2nd LOG will return 0.0000794

Hiting 2nd 5 will express it as 7.94 -5, giving you the [H+] concentration.

Apr 22, 2008 | Texas Instruments TI-30XA Calculator

1 Answer

Antilog in chemistry problem

pH is minus (log to base 10) of the hydrogen ion activity of an aqueous solution, or (log to base 10) of (1/hydrogen ion activity)

To get the inverse log, i.e the hydrogen ion activity corresponding to a specified pH, simply enter the pH value and press


Answer 0.001

Apr 22, 2008 | Texas Instruments TI-30XA Calculator

Not finding what you are looking for?
Texas Instruments TI-30XA Calculator Logo

541 people viewed this question

Ask a Question

Usually answered in minutes!

Top Texas Instruments Office Equipment & Supplies Experts


Level 3 Expert

102366 Answers


Level 3 Expert

7993 Answers

Stevan Milanovic

Level 2 Expert

261 Answers

Are you a Texas Instruments Office Equipment and Supply Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides