Why plotting the first derivative of my function gets shrinked on its amplitud?

x = linspace(-2*pi,2*pi,100); y1 = sin(x); y2 = diff(y1); figure plot(y2);

Answer 1

[Jan]

What is the derivative of sin(a * t)?

a * cos(a * t)

Try it:

x  = linspace(-2*pi, 2*pi, 100);
y1 = sin(x);
y2 = diff(y1);
figure
plot(x, y1, 'r');
hold('on');
plot(x, y2, 'g');

x2 = linspace(-2*pi, 2*pi, 200);  % Time with double resolution
y3 = sin(x2);
y4 = diff(y3);
plot(x2, y4, 'b')