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+--- Forum: HP Prime (/forum-5.html)
+--- Thread: Cross Product (/thread-4204.html)
Cross Product - rgallier - 06-23-2015 01:17 AM
Why won't this evaluate from Home in RPN:
CROSS([-6 4 12],[-0.3 0.4 0])
RE: Cross Product - kharpster - 06-23-2015 01:34 AM
(06-23-2015 01:17 AM)rgallier Wrote: Why won't this evaluate from Home in RPN:
CROSS([-6 4 12],[-0.3 0.4 0])
It does if you enter it "RPN Style" ;-)
[-6 4 12] Enter
[-0.3 0.4 0] Enter
CROSS Enter
The displayed result is: [-4.8 -3.6 -1.2]
RE: Cross Product - rgallier - 06-23-2015 01:53 AM
I kept trying:
[-6 4 12] ENTER
[-0.3 0.4 0] ENTER
CROSS(2)
Why do some functions need the stack arguments and others don't. I know cross product is implied with two arguments. If you put in CROSS(2) the error message even shows:
CROSS([-6 4 12] , [-0.3 0.4 0]); this format works with some vectors in RPN Home!?!
RE: Cross Product - kharpster - 06-23-2015 02:06 AM
(06-23-2015 01:53 AM)rgallier Wrote: Why do some functions need the stack arguments and others don't.
Do you have an example or two?
RE: Cross Product - rgallier - 06-28-2015 12:59 AM
erf() is one
http://h30434.www3.hp.com/t5/Calculators-and-Business-Handheld-Devices/HP-Prime-erf-function/td-p/5047983
RE: Cross Product - rgallier - 06-28-2015 01:21 AM
This video discusses some others:
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=7&ved=0CFEQtwIwBg&url=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DYAJwjpldiak&ei=lEuPVZSFB8L5-AG3moHACQ&usg=AFQjCNFziGDXZq5ZkusFirnPE5vHBnVQrQ&sig2=_gVlK2S3_SIyNoykyAOPZw&bvm=bv.96783405,d.cWw&cad=rja
RE: Cross Product - John Colvin - 06-28-2015 02:07 AM
(06-23-2015 01:53 AM)rgallier Wrote: I kept trying:I think that the answer is CROSS doesn't require a stack levels specifier if entered as a command (CROSS Enter) because it always takes two arguments.
[-6 4 12] ENTER
[-0.3 0.4 0] ENTER
CROSS(2)
Why do some functions need the stack arguments and others don't. I know cross product is implied with two arguments. If you put in CROSS(2) the error message even shows:
CROSS([-6 4 12] , [-0.3 0.4 0]); this format works with some vectors in RPN Home!?!
RE: Cross Product - rgallier - 06-28-2015 03:21 AM
I guess I was confusing the fact that CAS functions used in HOME require the stack argument; even if it is only one and always one. It just seems the UI inconsistencies provide for a confusing UX.
RE: Cross Product - kharpster - 06-28-2015 11:33 AM
(06-28-2015 03:21 AM)rgallier Wrote: It just seems the UI inconsistencies provide for a confusing UX.
Yes, yes they do! At times it's almost like using two completely different machines...