Question about Casio FX-260 Calculator

Ad

Use the log function (common logarithm). See screen capture for markings
on key.

To evaluate the negative of a logarithm

Enter the
number (argument) of the logarithm

Press the = key to have it
calculated.

While result is still displayed, press the sign change
key or (+/-).

Beware that -log(number) is not necessarily a
negative value.

Another way to calculate -log is to use the
relation

log(1/a)=-log(a) .

Your example

3 [EXP] [(] [+/-] 2 [) ] [LOG][=] [+/-]

[EXP] is the key to enter exponent of a power of 10 :It is a shortcut, so no 10 is entered. Respect the key sequence above.

[ (] left parenthesis to prevent ambiguity due to the negaticve exponent. Just a security.

[)] is the enclosing right parenthesis

[+/-] is the Sign Change key

Posted on Jun 22, 2010

Ad

Hi,

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.

goodluck!

Posted on Jan 02, 2017

Ad

You can do 0-log(number) or you can calculate the log value then negate it by pressing the change sign key marked (-) or +/- or (+/-).

Sep 06, 2012 | Texas Instruments TI-34II Explorer Plus...

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.

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

Depending on the actual log function you are talking about, the inverse function (what you call the anti log) can be one of several things.

The inverse of the natural log (LN) is the exponential function** e^x**.

**If y= ln(x) then x=e^y **

On a calculator functions that are inverse of one another share the same physical key.**If one function is marked on a key, the inverse function is usually the SHIFTED (or 2nd) key **

The inverse of the common (decimal logarithm) is the power function with 10 as base.

Example:** if y= log(x) then x=10^y**

For an arbitrary base (must be positive)** if y= log_b(x) then x=b^y**.

Note: I do not think that the FX-300ms can perform log calculations in bases other than e (natural log) or 10 (common decimal log).

The inverse of the natural log (LN) is the exponential function

On a calculator functions that are inverse of one another share the same physical key.

The inverse of the common (decimal logarithm) is the power function with 10 as base.

Example:

For an arbitrary base (must be positive)

Note: I do not think that the FX-300ms can perform log calculations in bases other than e (natural log) or 10 (common decimal log).

Aug 13, 2011 | Casio FX-300MS Calculator

Make sure you use the (-) key to enter negative values, not the - key. For example, to calculate the common antilog of -5, press

SHIFT log (-) 5 =

To calculate the natural antilog of -5, press

SHIFT ln (-) 5 =

SHIFT log (-) 5 =

To calculate the natural antilog of -5, press

SHIFT ln (-) 5 =

Apr 30, 2011 | Casio FX-115ES Scientific Calculator

You're not calculating the square of a negative number, you're calculating the negative of a square. You need to use parenthesis to indicate the square of a negative number.

You're calculating -(3^2), not (-3)^2.

To calculate the latter: ( (-) 3 ) x^2 =

You're calculating -(3^2), not (-3)^2.

To calculate the latter: ( (-) 3 ) x^2 =

Dec 05, 2010 | Texas Instruments TI-30XA Calculator

To enter an exponent, positive or negative, use the EE (Enter Exponent) key (the shifted function of the , key just above the 7 key). Do 5 2ND [EE] (-) 1 0 / 5 2ND [EE] (-) 1 0 ENTER and you'll see 1.

What I think you're doing (I can't be sure without seeing your keystrokes) is calculating

5*10^-10/5*10^-10 which is interpreted as (5*10^-10/5)*10^-10, which indeed is 10^-20.

What I think you're doing (I can't be sure without seeing your keystrokes) is calculating

5*10^-10/5*10^-10 which is interpreted as (5*10^-10/5)*10^-10, which indeed is 10^-20.

Oct 16, 2010 | Texas Instruments TI-84 Plus Silver...

Use the log function (common logarithm). See screen capture for markings on key.

To evaluate the negative of a logarithm

Enter the number (argument) of the logarithm

Press the = key to have it calculated.

While result is still displayed, press the sign change key or (+/-).

Beware that -log(number) is not necessarily a negative value.

Another way to calculate -log is to use the relation

log(1/a)=-log(a) .

To evaluate the negative of a logarithm

Enter the number (argument) of the logarithm

Press the = key to have it calculated.

While result is still displayed, press the sign change key or (+/-).

Beware that -log(number) is not necessarily a negative value.

Another way to calculate -log is to use the relation

log(1/a)=-log(a) .

Jun 01, 2010 | Casio FX-260 Calculator

You compute the negative of a logarithm the same way you compute the negative of anything else. However, do you really mean the antilog (inverse logarithm)? Use 2ND [e^x] for the natural antilog, 2ND [10^x] for the common antilog.

For negative exponents, as well as negative anything, use the (-) key next to the decimal point. For your example, 1 EE (-) 6

For negative exponents, as well as negative anything, use the (-) key next to the decimal point. For your example, 1 EE (-) 6

Feb 25, 2010 | Texas Instruments TI-30XA Calculator

Hello,

This post answers two questions

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

**[H+]=10^(-pH)**

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)

**Example**s

1. 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)

Calculating the pH

Shortcut:

For all H+/H3O+ concentrations of the form**1.*10^(a)** where a is** an integer number between 0 and -14**, the pH is the negative value of the exponent.

Concentration =10^(-3), pH=3

Concentration=10^(-11), pH=11

For other concentrations such as 3.567*10^(-8), one cannot use the shortcut above, but have to calculate the log of the concentration

[H+/H3O+] = 3.567*10^(-8)

pH= - log(3.567*10^(-8))

This is keyed in as follows (to minimize the number of parentheses)

**8 (-) [2nd][10 to x] [*] 3.567 [LOG] [=] (-)**

Here you have two (-) change sign, the first is entered after the exponent of 10, the other at the end of the calculation to take the negative of the displayed result.**You may notice that it is entered in the reverse order of the defining relation **- log(3.567*10^(-8)).

To verify your calculation, the result is 7.447696891 or just 7.45

If you have a problem with the first (-) try entering it before you type in 8.

Hope it helps** **and thank you for using FixYa

And please, show your appreciation by rating the solution**.**

This post answers two questions

- How to obtain the concentration knowing the pH?
- How to obtain the pH knowing the concentration

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

To obtain the [H+] you need to calculate the antilog. You write the definition in the form

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

1. Let the pH=5.5, what is the H+ concentration?

With [(-)] being the change sign key, then

[H+]:

Calculating the pH

For all H+/H3O+ concentrations of the form

Concentration =10^(-3), pH=3

Concentration=10^(-11), pH=11

For other concentrations such as 3.567*10^(-8), one cannot use the shortcut above, but have to calculate the log of the concentration

[H+/H3O+] = 3.567*10^(-8)

pH= - log(3.567*10^(-8))

This is keyed in as follows (to minimize the number of parentheses)

Here you have two (-) change sign, the first is entered after the exponent of 10, the other at the end of the calculation to take the negative of the displayed result.

To verify your calculation, the result is 7.447696891 or just 7.45

If you have a problem with the first (-) try entering it before you type in 8.

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

The problem is simple. You're trying to get an [H+] concentration which is obviously going to have a value of some number times ten raised to a negative power. Therefore, you have to insert the negative value of the pH into the 10^(x). When you insert said negative number you will come out with the right answer.

i.e.

The pH of a sample of human blood was calculated to be 7.41. What is the [H+] concentration of the blood?

10^(-7.41) = [H+]

[H+] = 3.9 E-8

(the answer should only have two sig. figs because the pH has two digits after the decimal.

i.e.

The pH of a sample of human blood was calculated to be 7.41. What is the [H+] concentration of the blood?

10^(-7.41) = [H+]

[H+] = 3.9 E-8

(the answer should only have two sig. figs because the pH has two digits after the decimal.

Jun 10, 2008 | Texas Instruments TI-84 Plus Calculator

779 people viewed this question

Usually answered in minutes!

×