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## Summary:

- One book I have states that any scientific calculator works with this function: ##\arctan:\mathbb{R}\rightarrow{[-\pi,\pi]}##. I want to check it

Considering the measure of angles in radians, that are real numbers, the concept of of trigonometric function spreads to all real numbers. Any real number can be considered as an angle of the first circumference and a ##\mathbb{K}## number of circumferences.

We can consider the function ##\tan:\mathbb{R}\rightarrow{\mathbb{R}}##. This function is not bijective, but if we consider, instead of ##\mathbb{R}##, ##[-\pi,\pi]## as the set origin (which is what scientific calculators make), then it is bijective, and it's possible to define the inverse function ##\arctan:\mathbb{R}\rightarrow{[-\pi,\pi]}##

How can I check this function is which it works in my calculator?

Hope to have explained (and translated) well. I'm learning english, as you can clearly see. If it is not admissible, please delete it.

Greetings!

We can consider the function ##\tan:\mathbb{R}\rightarrow{\mathbb{R}}##. This function is not bijective, but if we consider, instead of ##\mathbb{R}##, ##[-\pi,\pi]## as the set origin (which is what scientific calculators make), then it is bijective, and it's possible to define the inverse function ##\arctan:\mathbb{R}\rightarrow{[-\pi,\pi]}##

How can I check this function is which it works in my calculator?

Hope to have explained (and translated) well. I'm learning english, as you can clearly see. If it is not admissible, please delete it.

Greetings!

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