3 question on the HP50G
in [HP48]
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From: usenet1.20.quaxo on 25 Mar 2007 15:02 Hi Ryan, > I suspect you mean e^(i*pi), not (e^i)*pi. But as you have written it, > HPs parses it as (e^i)*pi. > > On my HP49+, 'e^i*\pi, where \pi represents the pi symbol, evaluates to > '\pi*EXP(i)' or (1.549740975483,2.64355906408) > > Whereas 'e^(i*\pi)' evaluates to -1. Yes I mean e^(i*pi), and when in Rad mode the calc correctly evals it to -1. If I switch to Deg though, and enter the very same expression, and push "eval", it isn't evaluated. If I ->num it, I get a complex number, where the real part is close to -1 and the imaginary part close to 0, but I don't get the correct answer (-1). Cristian
From: Virgil on 25 Mar 2007 16:23
In article <1174849367.444790.123840(a)y80g2000hsf.googlegroups.com>, usenet1.20.quaxo(a)spamgourmet.com wrote: > Hi Ryan, > > > I suspect you mean e^(i*pi), not (e^i)*pi. But as you have written it, > > HPs parses it as (e^i)*pi. > > > > On my HP49+, 'e^i*\pi, where \pi represents the pi symbol, evaluates to > > '\pi*EXP(i)' or (1.549740975483,2.64355906408) > > > > Whereas 'e^(i*\pi)' evaluates to -1. > > Yes I mean e^(i*pi), and when in Rad mode the calc correctly evals it > to -1. > If I switch to Deg though, and enter the very same expression, and > push "eval", it isn't evaluated. If I ->num it, I get a complex > number, where the real part is close to -1 and the imaginary part > close to 0, but I don't get the correct answer (-1). > > Cristian 'e^(ix)', for real x, evaluates as 'cos(x) + i*sin(x)', so that when you change the angle mode, you get different evaluations of those trig functions. One way to avoid that in most instances is to give x the units of radians. Right sift 6 fir the units menu, NXT twice, then the ANGL softkey. Then after entering x press the r softkey, and x will have a unit of radians attached. |