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Consider the differential equation (x^2+1) y" + 5 y' + 4y =0. The solution can be written as a power series: y = c0 + c1 x + c2 x^2 + c3 x^3 + c4 x^4 + c5 x^5 + ... Express c4 in terms of co. (That is, c4 = ? co.) Round your answer to two decimal places