Question about Texas Instruments TI-30XA Calculator

# Hello How do I enter '10 log (4)' in my ti30xa calculator? The answer should be 6... ps I know, very basic question. Haven't done this in forever

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1 0 * 4 LOG =

Posted on Sep 07, 2010

• Akina Sep 07, 2010

ah, of course!! was looking for a more complicated way... thank you

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Hi,
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Posted on Jan 02, 2017

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## Related Questions:

### How do you convert 4726 to base 10?

4726 seems to already be on base 10
it's 4*10^3 + 7*10^2 + 2*10^1 + 6*10^0

Mar 17, 2011 | Casio FX-115ES Scientific Calculator

### I have a TI30XA calculator and want to know how to multiply numbers using scientific notation. I have learned how to enter a number (e.g., 1.5 x 10 -6), but when I try to multiply it by something (e.g.,...

Press 2nd [SCI] to switch the calculator to display all results in scientific notation. The results are the same whether you do it in scientific notation or not, it's just how the number is displayed.

Feb 13, 2011 | Texas Instruments TI-30XA Calculator

### When I substract log(2) from log(4) I get .301029957, the answer should be 2, what is wrong?

The answer for the problem log(4) - log(2) is actually 0.301, so the good news is that your calculator is working properly! Here's a quick breakdown of the solution for the problem:

1) We know that log(x) = N means that 10^N = x. So in this case, we need to find a number that 10 can be raised to in order to get 4 and 2.
2) To get a better idea of what the answer to the problem will be, we look at the scale of the numbers. 4 and 2 are both smaller than 10. In order to raise any number to a power and get a smaller number, that power must be less than 1. If the power was 1 or greater, the answer would be more than 10. Therefore, we know that log(4) is a decimal less than 1 and log(2) is a decimal less than 1.
3) Now we'll simplify the problem. A logarithm rule states that:

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

We can use this rule to simplify the equation in the problem.

log(4) - log(2) = log(4/2)

Since 4/2 = 2,

log(4) - log(2) = log(4/2) = log(2)

4) Now to solve the equation, the only thing that must be calculated is log(2). This would be done on a calculator. In step 2, we analyzed that log(2) must be less than 1. Therefore, the calculator is correct with the answer 0.301.

Hope this helped!

Nov 30, 2010 | Texas Instruments TI-84 Plus Calculator

### DB to Power ratio using antilog

The conversion formula is
# dB =10*log(Pout/Pin) for say an amplifier.
Pout/Pin= 10^4 then #dB =10*log(10^4)=10*4=40 dB

Let us take a less obscure exemple

# dB= 57.39, what is the power ratio?
10*log(Pout/Pin)= 57.39
log(Pout/Pin)=57.39/10=5.739
Pout/Pin=Ratio =10^(5.739)= 548276.9649, not a number you would hear or see quoted, but a correct value.

To calculate the power ratio
1. Convert the decibels in Bels (divide by 10)
2. While the number just calculated is still in Answer memory (ANS), press [SHIFT] [LOG] to access the the 10^x function
3. Press [SHIFT][(-)] to enter (ANS)
4. Close the parenthesis [)]
5. Press [ENTER]
Here is the screen capture for the calculation one way and back.

Mar 02, 2010 | Sharp EL-531VB Calculator

### Have a TI30Xa, i am trying to input 100 micro squared. how do I do this?

Usually you do not use the prefix micro by itself, it must be followed by the name of a unit: 1 micrometer=10^-6 meter. This being said, you want to enter 100*10^-6 and raise it to power 2.
For this you can use the exponent rules.
1. 100*10^-6=(10^2)*(10^-6)=10^(2-6)=10^-4; product of powers =>algebraic sum pf exponents
2. (10^-4)^2=10^(-4*2) =10^(-8) ; power of power =>product of exponents.
With your calculator: You have a key near which is written [10 to x]; you access the function with [2nd][10 to x]

In what follows, I will enter (10^-6)* 100 and square it. I will use the change sign (-) or [+/-] key
(-6) [2nd][10 to x] [*] 100 [=] [x^2] [=]

The first = calculates 100*10^(-6), the second [=] calculates the square of the number obtained after the first [=].
There are other ways that use parentheses to avoid ambiguities, but I think this is the safest one for you. Be warned that the result will most likely be displayed in scientific format, 1.00 -08 where the -08 will be raised with respect to the main level line. If not, the result will be 0.00000001

Feb 17, 2010 | Texas Instruments TI-30XA Calculator

### How do i enter pH on a TI 30 calculator

Hello,
1. How to obtain the concentration knowing the pH?
2. How to obtain the pH knowing the concentration
If you are not interested in the theory, jump to the examples at the end of the post.

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)
Examples

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

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

### I am asked to find the log of 6.02 X 10 to the 23rd power> How can I find 10 to the 23rd power?

Hello,
Why complicate matters for yourself?
You were asked to calculate log(6.02x10^23), let your finger do the calculating.
I checked the claculator manual and you have to enter it all at one go. Pay attention to the key strokes. You will not do it in such a laborious manner

23[10^x] [=] gives 10^23
23[10^x]*6.02 [=] multiplies 6.02 by 10^23 to give you Avogadro s number.

To find its logarithm in base 10, you have to enter the number then press [LOG] . When you press [LOG] you are calculating the log of the last result. You obtain 23.77959649.

If I had given you the key strokes directly you might have not understood why I do things this way. Now the actual key strokes you enter

23[10^x] * 6.02 [LOG] [=]

If you are only looking for your result, you are done. You can ignore what follows.

If you know the rules for the logarithms, you can do the calculation more easily. log here is log in base 10

Rule 1 Log(a*b)= log(a) + log(b)
Rule 2 Log(c^n) = n* log(c)
Rule 3 log(10)=1

Thus applying the rules
log(6.02*10^23) = log(6.02) + log(10^23) first rule applied
= log(6.02) + 23*log(10) 2nd rule applied
= log(6.02) + 23 3rd rule applied
= 0.77959649 + 23= 23.77959649
Hope it helps

Oct 10, 2009 | Texas Instruments TI-30XA Calculator

### How can I use the Log function on my calculator?

Hi ;

for log base 10 use the the "log" key

example :

log(2) + log(3) = log(6)

enter 2 press the log key you will get 0.30102999 press the '+" key than 3 log you should get 0.47712125 for it Press the "=" or enter and you should get 0.778151250 for a answer than press inv or 2nd log and you should get 6 for a answer

and that all there is to it

Oct 07, 2009 | Texas Instruments BA-II Plus Calculator

### 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.

Example:

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

### How to calculate log value in calculator with different base value

In any scientific calculator log2(n) can be  calculated with either ln or log function as follows

Log2(n)= ln(n) / ln(2)

Or
Log2(n)=log(n) / log(2)

both will give nearly the same answers

Dec 08, 2007 | Casio FX-300MS Calculator

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