To construct an approximate polynomial expression for a sequence that has constant fourth differences of 48, I start by noting that because the fourth difference is constant, the polynomial must be of degree 4. I first determine the leading coefficient, which is connected to the fourth difference. Since the fourth difference is 48, I divide it by 24 (the factorial of 4) to find the leading coefficient of the polynomial; this gives me a coefficient of 2.
Next, I write the polynomial in its general form as \(P(n) = 2n^4 + an^3 + bn^2 + cn + d\), where \(a\), \(b\), \(c\), and \(d\) are constants that I still need to determine. To find these constants, I would use initial conditions or values from the given sequence to create a system of equations. This allows me to solve for \(a\), \(b\), \(c\), and \(d\). Finally, after substituting these constants back into the polynomial, I’ll have the desired expression that approximates the original sequence.