Bug 488613

Summary:	tan(π / 2) does not return undefined in radian mode
Product:	[Applications] kcalc	Reporter:	Yorimirus <misawalach00>
Component:	general	Assignee:	Gabriel Barrantes <gabriel.barrantes.dev>
Status:	CONFIRMED ---
Severity:	normal	CC:	fanzhuyifan, gabriel.barrantes.dev
Priority:	NOR
Version First Reported In:	24.05.0
Target Milestone:	---
Platform:	openSUSE
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Yorimirus 2024-06-17 08:54:25 UTC

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SUMMARY

Inputting tan(π / 2) into KCalc does not return a correct value. 
You can get pi in the Constants>Mathematics dropdown, which is what I used.

STEPS TO REPRODUCE
1. Set input mode to RAD
2. Input tan(pi / 2)
3. Press enter to calculate the result

OBSERVED RESULT

KCalc returns -6,05546978455e+12

EXPECTED RESULT

KCalc should return "undefined" or nan or some other value indicating there is no result.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma:  openSUSE Tumbleweed, KDE Plasma 6
(available in About System)
KDE Plasma Version: 6.0.5
KDE Frameworks Version: 6.3.0
Qt Version: 6.7.1

ADDITIONAL INFORMATION

Entering tan(90) in the degree mode seems to return nan like it should, so maybe this is a rounding error?

Desmos, Photomath and Wolframalpha return correct values.

Comment 1 Gabriel Barrantes 2024-06-20 23:50:59 UTC

This is an old bug that is now more notorious due to the input display showing the "π", it is a rounding error, the π symbol gets converted to its decimal form and not to the originally intended KNumber Pi(), (https://invent.kde.org/utilities/kcalc/-/blob/master/knumber/knumber.h?ref_type=heads#L42)... I will look into it...