[BUG] Degrees on CAS

[Tugdual]

Context: CAS/Home in degrees

Test 1
Enter cos(90) in CAS just to check you get 0 and are indeed in degrees

Test 2
Enter acos(cos(pi/2)) you get 90
Home returns 1.57 as expected.

Test 3
Enter asin(sin(pi)) you get 0
Home returns 3.14 as expected

[Terje Vallestad]

(02-25-2014 10:12 AM)Tugdual Wrote:  Context: CAS/Home in degrees

Test 1
Enter cos(90) in CAS just to check you get 0 and are indeed in degrees

Test 2
Enter acos(cos(pi/2)) you get 90
Home returns 1.57 as expected.

Test 3
Enter asin(sin(pi)) you get 0
Home returns 3.14 as expected

I notice if you remove the tick for Exact in CAS settings, you get the same results as in Home

Cheers, Terje

[Tugdual]

Well done Terje. I'll remember you shall not ask the Prime for an Exact result if you want the correct one. Huh what?

[Terje Vallestad]

(02-25-2014 01:23 PM)Tugdual Wrote:  Well done Terje. I'll remember you shall not ask the Prime for an Exact result if you want the correct one. Huh what?

Given that "the number π is a mathematical constant that is the ratio of a circle's circumference to its diameter", it may not be too far fetched that the system treats π/2 as 90 in Exact mode?
Maybe others have a clearer understanding/explanation for that?

Cheers, Terje

[parisse]

Will be fixed with the next release. It was not found before because CAS users generally work in radian. And if you work in degree, there is no reason to enter something like cos(pi).

[Tugdual]

(02-25-2014 05:56 PM)parisse Wrote:  Will be fixed with the next release. It was not found before because CAS users generally work in radian. And if you work in degree, there is no reason to enter something like cos(pi).

Except when you test this asin(acos(atan(tan(cos(sin(9)))))
and the result is asin(sin(9)-1/2*pi+90)

pi came on its own, I didn't pull it... and I started suspecting more.