 CAS fourier_an ... - Printable Version +- HP Prime Forum (http://forum.hp-prime.de) +-- Forum: HP Prime (/forumdisplay.php?fid=1) +--- Forum: Questions to HP (/forumdisplay.php?fid=3) +--- Thread: CAS fourier_an ... (/showthread.php?tid=50) CAS fourier_an ... - REF - 17-01-2016 02:38 PM Hello friends, I try to use the new Funktion "fourier_an", "..._bn" or "..._cn" on CAS. The function I try to approximate is a rectangle signal. T=10ms f(x)= 10V = û a=0 n=1...6 In CAS: fourier_bn(Expr,Var,T,n,a) so I type fourier_bn(10,x,10,1,0) for b1 Normally the result is: b1=û*2/PI=20/PI b2=0 b3=û*2/(3*PI)=20/(3*PI) b4=0 b5=û*2/(5*PI)=20/(5*PI) b6=0 a0=û/2=5 But with HP Prime calculator: b1=b2=b3=b4=b5=b6=0 a0=10 The results are compleately wrong!!! Is there a mistake in using the function on my side or is it an bug? Thank you in advance for your help. REF RE: CAS fourier_an ... - JMB - 18-01-2016 06:06 PM Hi! I assume that your function has a value of 10 V for the first 10 ms, and 0 V for the next 10 ms; in that case the period is 20 ms. So, if you use fourier_an() and fourier_bn() with a function whose value is: 10 if x<10, and 0 if x>=10, and use 20 as the period, you'll get the correct answer. a0=5 b1=20/PI b2=0 b3=20/(3*PI) ... RE: CAS fourier_an ... - REF - 13-04-2016 09:43 PM Can you show me how to type in? fourier_an(10,x,20,0,0) fourier_bn(10,x,20,1,0) . . . Is this right? REF (18-01-2016 06:06 PM)JMB Wrote:  Hi! I assume that your function has a value of 10 V for the first 10 ms, and 0 V for the next 10 ms; in that case the period is 20 ms. So, if you use fourier_an() and fourier_bn() with a function whose value is: 10 if x<10, and 0 if x>=10, and use 20 as the period, you'll get the correct answer. a0=5 b1=20/PI b2=0 b3=20/(3*PI) ... RE: CAS fourier_an ... - JMB - 29-04-2016 05:46 PM Please see the following screen capture: [attachment=63] The function: 10 if x<10, 0 if x >=10 is entered by pressing the template key, and then selecting the 5th icon of the 1st row: [attachment=62] RE: CAS fourier_an ... - REF - 27-09-2016 09:14 PM (29-04-2016 05:46 PM)JMB Wrote:  Please see the following screen capture: The function: 10 if x<10, 0 if x >=10 is entered by pressing the template key, and then selecting the 5th icon of the 1st row: Thank you very much!!! It works fine. :-)