finding power values in time domain of a signal

hi , i have a signal and i would like to find the power domain values of my signal at a particular time samples

x = linspace(0,1,1000); base = 4*cos(2*pi*x); Pos = [1 2 3 5 7 8]/10; Hgt = [3 7 5 5 4 5]; Wdt = [1 3 3 4 2 3]/100; for n = 1:length(Pos) Gauss(n,:) = Hgt(n)*exp(-((x - Pos(n))/Wdt(n)).^2); end PeakSig = sum(Gauss)+base; plot(x,Gauss,'--',x,PeakSig,x,base)

findpeaksGSS(x,y,0.0004,0.3,17,21,3)---> This is an example signal and i did peak finding using findpeakGSS(x,x,x....) which gives the result of peaks position and starting and end values of a detected peak

Result as 1st Peak No(1), Position (0.099), width(0.0284), Area(0.1852), Start (0.0628), End (0.136)

So here i would like to find the power values of my signal at start(0.0628) & end(0.136) points of my signal

as i know power_timedomain = sum(abs(x).^2)/length(x) will give the total power of the signal