How to do Fourier Integrals on the HP Prime?

[Stevetuc]

(12-09-2019 08:22 PM)medwatt Wrote:  

(12-09-2019 12:23 PM)Stevetuc Wrote:  https://www.hpcalc.org/details/9041



It uses the following to calculate the Fourier transform

Code:


//   // Function.F2 Fourier( f(t) ) = ABS( laplace( f(t) ) with (i*X) as independant )
//   ABS(simplify(laplace(F1(x),x)))
//   subst('  ',('x') = ('i*X'))
//

This is just evaluating the Laplace Transform at s=jw. The Laplace Transform used on the Prime is the single-sided LT, meaning it evaluates the integral from 0 to inf. You can use this LT to get the FT if you have a function that is right-sided. What happens if you want the FT of functions such as sin(wt), a dc signal, that span the the entire time domain ? Well, it's not possible.

Yes indeed. I shared the above code fragment to make that fact clear!
You may have to move back to TI or Casio, assuming you have an app that meets your needs or Wolfram.