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How to plot a smooth graph?

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donghun lee
donghun lee on 2 Apr 2020
Commented: donghun lee on 2 Apr 2020
clc,clear all
b0 = 0.015;
b1 = 0.015;
b2 = 0.035;
b3 = 0.050;
v = 40; %velocity
L = 2;
w = (2*pi*v)/L; %angular frequency
F = w*(1/(2*pi)); %in Hz
t = linspace(0,10,18);
b = b0 + b1*sin(w*t) + b2*sin(2*w*t)
+b3*sin(3*w*t);
plot(t,b)
Hi, I want to make this graph as being a smooth graph.
Thank you for your time.
  1 Comment
Rik
Rik on 2 Apr 2020
Although you could resample your function to draw a smooth curve through your data points, that would not accurately describe your function. You can greatly increase the number of points in your t vector to see that you have an enormous amount of aliasing going on here. See this Wikipedia page for more information.

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Accepted Answer

Birdman
Birdman on 2 Apr 2020
Edited: Birdman on 2 Apr 2020
You need to increase the step size of your t vector:
t = linspace(0,10,100);
Code:
b0 = 0.015;
b1 = 0.015;
b2 = 0.035;
b3 = 0.050;
v = 40; %velocity
L = 2;
w = (2*pi*v)/L; %angular frequency
F = w*(1/(2*pi)); %in Hz
t = linspace(0,10,100);
b = b0 + b1*sin(w*t)+b2*sin(2*w*t)+b3*sin(3*w*t);
plot(t,b)
  5 Comments
donghun lee
donghun lee on 2 Apr 2020
Ah!! Thank you soooo much for your help. I got what you mean now! I really appreciate it.
Thank you for your time again Rik!

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More Answers (1)

Walter Roberson
Walter Roberson on 2 Apr 2020
t = linspace(0,10,18);
Increase the 18 to something larger, such as 50.
  1 Comment
donghun lee
donghun lee on 2 Apr 2020
Thank you very much for your comment.

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