clear; clc; close all;

x = linspace(0, 4 * pi, 10);
y = sin(x) .* exp(-x / 5);

plot(x, y, "o"); hold on;
xq = linspace(0, 4 * pi, 100);
yq1 = interp1(x, y, xq);
plot(xq, yq1, "--");
yq2 = interp1(x, y, xq, "spline");
plot(xq, yq2, "b--");

x = linspace(0, 4 * pi, 100);
y = sin(x) .* exp(-x / 5);
plot(x, y, "k--");