cumsum function question for integration
49 vues (au cours des 30 derniers jours)
Afficher commentaires plus anciens
The code is below.
close all;
clear all;
clc;
format long;
syms t;
inter_val = 0.0001;
tn=0:inter_val:20;
t=tn;
y_cos = sin(t);
int_y_cos=cumsum(y_cos*inter_val);
figure(1);
plot(t, y_cos, 'k');
box on; grid on;
figure(2);
plot(t, int_y_cos, 'r');
box on; grid on;
I want to know why figure(2) didn't come out with cos plot but with offset?
But switch y_cos = sin(t) to y_cos = cos(t), it can give a perfect sin plot?
Thanks,
0 commentaires
Réponse acceptée
Plus de réponses (1)
Cris LaPierre
le 21 Sep 2022
It has to do with the fact that sin(t) starts at 0 and is positive until pi. cumsum is just adding up the Y values, so it oscillates between 0 and 2. With cos(t), it is only positive for pi/2, so cumsum only gets to half the value before it starts decreasing, or 1. It then is negative for pi, decreasing the value by 2, reaching -1. It therefore oscillates between -1 and 1.
0 commentaires
Voir également
Catégories
En savoir plus sur Function Creation dans Help Center et File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!