“Write the first 5 terms of y”(x).”
where y”(x) is the second derivative of y(x) expanded as a series solution.
This SWBQ helps students to see what happens to a power series when derivatives are taken as a lead-in to reindexing a sum.
After the terms have been written, discuss how the terms can be reindexed so that the sum has the same powers of xn as other sums in the differential equation.