# Why do calculators not include SEC, COT and CSC?

**URL:** <https://boards.straightdope.com/t/why-do-calculators-not-include-sec-cot-and-csc/139195>\
**Category:** Factual Questions\
**Created:** [November 27, 2002, 8:44pm UTC](https://boards.straightdope.com/t/why-do-calculators-not-include-sec-cot-and-csc/139195 "2002-11-27T20:44:22Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Muad\_Dib](https://avatars.discourse-cdn.com/v4/letter/m/35a633/32.png) [@Muad\_Dib](https://boards.straightdope.com/u/Muad_Dib)\
**Post date:** [November 27, 2002, 8:44pm UTC](https://boards.straightdope.com/t/why-do-calculators-not-include-sec-cot-and-csc/139195/1 "2002-11-27T20:44:22Z")

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I know that for scientific calculators it would be a little redundant. However, for calculators that do symbolic manipulation (ie, TI-92) it would be a **big** help to have those functions built in. A function can be much, much clearer when it is not always “simplified” in terms of SIN, COS, and TAN.

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**Author:** ![Pythagras](https://avatars.discourse-cdn.com/v4/letter/p/45deac/32.png) [@Pythagras](https://boards.straightdope.com/u/Pythagras)\
**Post date:** [November 27, 2002, 8:51pm UTC](https://boards.straightdope.com/t/why-do-calculators-not-include-sec-cot-and-csc/139195/2 "2002-11-27T20:51:05Z")

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you can probably redefine sec, cot, csc on a ti92, I know you can on a TI-89. They probably dont include it because of the limitted space.

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**Author:** ![Achernar](https://avatars.discourse-cdn.com/v4/letter/a/e274bd/32.png) [@Achernar](https://boards.straightdope.com/u/Achernar)\
**Post date:** [November 27, 2002, 8:52pm UTC](https://boards.straightdope.com/t/why-do-calculators-not-include-sec-cot-and-csc/139195/3 "2002-11-27T20:52:57Z")

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Okay, first off, you know you can define sec(x) = 1/cos(x), right? But you want more. You want to be able to put in d(sec(x), x) and get back out sec(x) \* tan(x), right? Right now, if you do it, you get sin(x) / (cos(x))[sup]2[/sup]. But really, I think it would be ambiguous. How would the calculator know that you want sec(x) \* tan(x), and not sin(x) \* (sec(x))[sup]2[/sup], and not sec(x) / cot(x)?

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**Author:** ![Muad\_Dib](https://avatars.discourse-cdn.com/v4/letter/m/35a633/32.png) [@Muad\_Dib](https://boards.straightdope.com/u/Muad_Dib)\
**Post date:** [November 27, 2002, 11:47pm UTC](https://boards.straightdope.com/t/why-do-calculators-not-include-sec-cot-and-csc/139195/4 "2002-11-27T23:47:41Z")

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Hmmm… Good question.

Would it really be that hard to create an algorithm that would derive the simplest form of the equation?

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**Author:** ![Achernar](https://avatars.discourse-cdn.com/v4/letter/a/e274bd/32.png) [@Achernar](https://boards.straightdope.com/u/Achernar)\
**Post date:** [November 28, 2002, 5:49am UTC](https://boards.straightdope.com/t/why-do-calculators-not-include-sec-cot-and-csc/139195/5 "2002-11-28T05:49:36Z")

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No, but you have to say unambiguously what you mean by simplest form. I think that getting it in terms of sines and cosines is a reasonable definition of simplest form.