arccos problem

arccos os .7041 returned 1... instead of 45 when in degrees mode.

You're right. There is a problem with arc functions in version 1.5, It will be fixed in the next release (1.6).
Thank you for bringing this to my attention.

cheers,
Saeid

This issues is now fixed in version 1.6 which is just released. You may download the new version from here:

http://calculator.runiter.com/math-calculator/

Saeid