why "symsum(si​n(k*pi)*k,​0,n)" not equal zero

2 visualizzazioni (ultimi 30 giorni)
murat
murat il 23 Feb 2014
Risposto: Walter Roberson il 23 Feb 2014
why "symsum(sin(k*pi)*k,0,n)" not equal zero?

Risposte (3)

Walter Roberson
Walter Roberson il 23 Feb 2014
symsum(sin(k*sym('pi'))*k,0,n)
Remember, "pi" in MATLAB is only a numeric approximation to the transcendental number; you need to use the transcendental number rather than the numeric approximation.

Jan
Jan il 23 Feb 2014
What is n? For e.g. n=0.5 the result is not surprising.

Paul
Paul il 23 Feb 2014
I don't think Matlab recognizes that sin(pi)= 0, therefore it cant simplify further sin(pi*n)*(n/2 + 1/4). Just type sin(pi) and you will see you won't get 0. sind(180) does give 0 but sind doesn't support symbolic variables.

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by