I keep getting a negative number when i try to do tan40

It is not possible to take the logarithm of a negative number because the logarithm function is defined only for positive real numbers. If you are trying to take the logarithm of a negative number, you will encounter a "domain error" because the input is outside the domain of the function.
To fix this error, you will need to make sure that the input to the logarithm function is a positive real number. One way to do this is to add a condition to your code to check whether the input is positive before taking the logarithm. For example:

if x > 0:
y = log(x)
else:
print("Error: Cannot take log of non-positive number")

Alternatively, you can use the logarithm function from a library that supports complex numbers, such as the cmath library in Python, which import cmath
x = -1
y = cmath.log(x)
print(y) # Output: (-3.141592653589793j)
allows you to take the logarithm of negative numbers by using the complex logarithm function log(). For example:

Keep in mind that the complex logarithm function returns a complex number, so you may need to handle the result differently than you would with a real logarithm.

Try this: =IF(B13+(B13*B$7/12-B$10)<0,0,B13+(B13*B$7/12-B$10))

a negative number is any number less than zero. for example if you subtract 4 form 3 you get -1 which is negative one.

It is much better to get sleeves to keep your negatives in, in order to use them you have to keep them clean and dry. You might also want to look into digitally scanning your negatives to better preseve them.

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.

1 0 * 4 0 TAN =

Actually, you're negating a square, not squaring a negative. When you put in -x^2, it's getting calculated as -(x^2). In order to square a negative number, use parentheses and calculate it as (-x)^2.

Also, make sure you're using the +- key to the right of th decimal point instead of the - key when entering the negative number.

Having gone over a month without a response to my query, I assume this is no longer a problem.

Sounds like one department is selling / transferring from another department.. You should see offsetting numbers in the other departments to track it down. Just look for positive entries in other departments that match the negative entries, and verify with date & time stamp and item / SKU number. May be a programming error.

You must put all negative numbers in Parenthesis otherwise your calculator is not squaring the negative .