Which steps with my calculator are needed to obtain result in radians?

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  • Thread starter mcastillo356
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Summary:

I've read more than one time the guideline, but not obtained the result related to ##\pi##
Hi PF, hope to be publishing in the right forum
<moderator's note: moved to the right forum :smile:>
##\arccos{\dfrac{\sqrt{2}}{2}}\mbox{rad}=\dfrac{\pi}{4}\mbox{rad}##
This is a trigonometric true, but I've read the steps in my guideline, and I don't manage. The calculator is a chinese Kooltech CPC-400N, an imitation of Casio fx-82MS. It should work similarly.
I enter the data, and the result is 0,785398163. Right, but, how could I obtain ##\dfrac{\pi}{4}##?
Greetings!
 

Answers and Replies

  • #2
DrClaude
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The calculator makes numerical computations, not symbolic ones. To get the results in terms of π, you have to divide by it.
 
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  • #3
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Thank you very much, DrClaude! Understood. Divided by ##\pi##, ##0,249999999\Rightarrow{\dfrac{\pi}{4}}##
Greetings!
PD: You meant multiply and divide by ##\pi##, isn't it?
 
  • #4
DrClaude
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Thank you very much, DrClaude! Understood. Divided by ##\pi##, ##0,249999999\Rightarrow{\dfrac{\pi}{4}}##
Greetings!
PD: You meant multiply and divide by ##\pi##, isn't it?
You divide by π to get the multiplicative factor to apply to π.
 
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  • #5
Wrichik Basu
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I enter the data, and the result is 0,785398163. Right, but, how could I obtain ##\dfrac{\pi}{4}##?
You can't if you use Casio fx-82MS (or a clone) that has S-VPAM. For displaying fractions, you need a calculator with a natural textbook display (natural-VPAM), like fx-991ES plus.

20201127_172027.jpg
(Sorry for the bad image quality)
 
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  • #6
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Thank you, Wrichik Basu (good image)!
DrClaude, I've understood: if I divide by ##\pi##, the result is how many times 0,785398163 contains ##\pi##. Left aside my poor english, I'm I right?
 
  • #7
DrClaude
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DrClaude, I've understood: if I divide by ##\pi##, the result is how many times 0,785398163 contains ##\pi##. Left aside my poor english, I'm I right?
Yes.
 
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  • #8
Lnewqban
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1920px-Degree-Radian_Conversion.svg.png
 
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  • #9
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Thank you very much, Lnewqban! Still there is something I would like to ask... I will leave it for a while; I want to try if I can manage. It's another thread: how to calculate the unique phase of a complex number, that's it, ##\mbox{arg}## in the interval ##(-\pi,\pi]##, ##\mbox{Arg}##
Greetings!
 
  • #10
Lnewqban
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You are welcome, Castillo. :smile:
Sorry, I know nothing about argument.
 
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  • #11
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Some calculators have an atan2 function or similar that takes care of the sign, otherwise you need to do that manually. Calculate the arctangent of (imaginary part/real part) and then add/subtract pi as needed based on the sign of the imaginary and real part.
 
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