504 Apprridis A Sohitions to the Exercises Solution 11.5 Solution 11.6 a,) I n grncral, t,he sum of licrioclic hiiictioiis is only pcriodic if cnch period is a rat,ioiial proportiori of t,he otliers The period of the sLiirirrirtl signe,l 2' is t,llrli tlic snisllest common inultiplc of the individual periods, aiid the fuiidn.menta1 frequency of thc signal f = is t,hr largest coimnion divisor of t,hc individual fuiiclament,al frequencies 2, it): x2(t) fiindnmeiital freqiieiiry of circnit 3u?0 period siii(dOtjcos(&wot) = Yi + = 0.5 Isirl((1 - f i ) i ~ o t ) sin((1 + JT)q,t)]