%% Calculate the power of the sum of a signal and the same signal shifted in phase
clear all; close all; clc;

% Generate signal
fs = 100000;
t = 0:1/fs:1;
fi = 0:0.0174532925:pi;
s = sin(2*pi*t) + sin(2*pi*t + fi');

% Calculate power
P = 1/length(t)*(sum(s, 2).^2);

figure;
plot(fi, P); xlabel("Phase angle [rad]"); title("Power of the sum of two signals shifted in phase");