Suppose that s(t) is a real-valued signal. We have a set of orthonormal basis functions {ϕi(t)}N i=1 with which we wish to approximate s(t) as s ˆ(t) = N∑ i =1 siϕi(t) such that the energy in the error signal e(t) = s(t) − s ˆ(t) E e = ∫−[infinity] [infinity] e2(t)dt = ∫−[infinity] [infinity] (s(t) − s ˆ(t))2dt is minimized. Calculate the optimum coefficients {si}N i=1 that minimize Ee.