Overall impulse response h[n] is given by h[n]=h 1 [n]+h 2 [n]*(h 3 [n]+h 4 [n])- =h 1 [n]+h 2 [n]*h 3 [n]+h 2 [n]*h 4 [n] ..
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solution in drawing..

With the simplified model of the eye, what corrective lens (specified by focal length as measured in air) would be needed to enable a person underwater to focus an infinitely distant object? (be careful-the focal length of a lens underwater is not the same as in air! assume that the corrective lens has a refractive index of 1.62 and that the lens is used in eyeglasses, not goggles, so there is water on both sides of the lens. assume that the eyeglasses are 1.90