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Regarding units of output value

Posted 7 months ago
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Hi All, I am using the following command, to find maximum of a function:

FindMaximum[Cos[phi Degree] (1 - 0.4 Sin[5 Degree + phi Degree]^2), phi]

And getting the following Out put:

{0.998309, {phi -> -2.22083}}

I know Mathematica by default use the values of an angle in Radians, therefore, I used the Degree with angles in INPUT.

Now, I am not sure about the value of output given in Mathematica. Whether its' phi=-2.22083 Degree OR -2.22083 Radians?

9 Replies

Regarding units of output value

I’d expect the output to be in radians. All the Degree multiplier does is convert the specified value form degrees to radians. Try typing Degree//N to get its numeric value. If you want to retain the units in the output, you could try wrapping the angular variables, x, in Quantity[x,”AngularDegrees”] - tip, you can generate a nicely formatted version of this Quantity expression by typing ctrl= followed by “x Angular Degrees”. This might return a Quantity result (in this case either radians or angular degrees). I’m not sure whether it would have the desired outcome, but might be worth a go to see what you get.

Thanks for the reply. Can you elaborate : "you could try wrapping the angular variables, x, in Quantity[x,”AngularDegrees”] "

Do you mean I use the command FindMaximum[Cos[phi] (1 - 0.4 Sin[5 Degree + phi]^2), phi "AngularDegrees"]

Sorry, haven't been near my computer for a while. Having checked, I don't think my suggestion works, I wasn't sure that it would - see attached notebook. But the value of phi in your output is definitely in radians.

Attachments:

Thank you for this very nice demonstration. I realised that, in my original function, some of the quantities are in Radians and some are in Degree. Therefore, my results were not consistent.

Thanks for your time.

The result is in terms of degrees. Plot the input expression with phi ranging from -90 to 90 and you will see this.

Yes, you're quite right. My mistake.

Yes, you're quite right. My mistake.

Regarding units of output value

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