calculator cannot take a natural log of a negative number --states Not a Number

When I input a -1 and take the ln function for natural logarithm, it returns "Not a Number". I upgraded to 10.13.1 and now the calculator doesn't seem to work correctly.

Mac mini, macOS High Sierra (10.13.1)

Posted on Nov 15, 2017 6:50 PM

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Posted on Nov 15, 2017 6:54 PM

The natural logarithm function ln(x) is defined only for x>0.

So the natural logarithm of a negative number is undefined.

ln(x) is undefined for x ≤ 0

16 replies

Nov 15, 2017 8:36 PM in response to MarkFly

Folks, I misstated the issue as I tried using the ln function to reverse e^x. The real problem is that when I input a -1 and apply the e^x function, it returns "Not a number". This function is defined for x in (-infty, +infty) and so should produce a real value. I played around with the inverse function ln and it seems to work for real valued results of e^x once that works, but e^x seems to work only for positive values. To compute the values I want I have to go thru the rigamarole of calculating e^x for positive values and then inverting it to 1/e^x. That comes out just fine, but what a pain! Try putting -1 into e^x and see what happens!

Nov 16, 2017 5:24 AM in response to MarkFly

MarkFly wrote:


To compute the values I want I have to go thru the rigamarole of calculating e^x for positive values and then inverting it to 1/e^x. That comes out just fine, but what a pain! Try putting -1 into e^x and see what happens!

Not sure why it's "a pain". It requires the same number of clicks whether you enter a negative or positive value. Three.

Nov 16, 2017 6:36 AM in response to William Tomcanin

William Tomcanin wrote:


I'm seeing the same issue... upon entering "1" and "+/-" to invert the sign, pressing e^x gives the result "0" (incorrect).


Doing the same sequence of operations but pressing 10^x yields 0.1, the correct result.


There appears to be an issue with the calculator app.

Yes, there is something wrong with the Calculator but .1 is incorrect.

Try this in order.

User uploaded file

(fixed)

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calculator cannot take a natural log of a negative number --states Not a Number

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