function powerdemo(vhat,ihat,phi)
phirad = phi*pi/180;
t = linspace(0,10);
v = vhat*cos(t);
i = ihat*cos(t+phirad);
Pavg = vhat*ihat*cos(phirad)/2*ones(size(t));


figure(1)
plot(t,v,t,i,t,v.*i,t,Pavg,'r--','linewidth',2)
set(gca,'fontsize',14)
legend('Voltage (V)','Current (A)','p(t) (W)','Average Power (W)')
hold on
plot(t,zeros(size(t)),':k')
xlabel('time')
hold off