To create an approximate polynomial expression for a sequence with constant fourth differences of 48, I recognized that a polynomial of degree 4 would be suitable due to the constant fourth differences. Knowing that the fourth difference is consistent, the polynomial's leading coefficient can be determined by dividing this value by 24, which is the factorial of 4. In this case, dividing 48 by 24 gives a leading coefficient of 2.
I then expressed the polynomial in a general form: \(P(n) = 2n^4 + an^3 + bn^2 + cn + d\), where \(a\), \(b\), \(c\), and \(d\) are constants that need to be determined. To find these constants, I utilized initial values from the given sequence to set up a system of equations. By solving this system, I was able to determine the values of \(a\), \(b\), \(c\), and \(d\). After substituting these constants back into the polynomial, I arrived at the desired expression that approximates the original sequence.