The error mesh function, en=ue(tn)−un=Icos(ωnΔt)−Icos(˜ωnΔt) is ideal for verification and further analysis! en=Icos(ωnΔt)−Icos(˜ωnΔt)=−2Isin(t12(ω−˜ω))sin(t12(ω+˜ω))