In 9-18, a geometric sequence is given. Find the common ratio and write out the first four terms. {Sill = {( -5)"}

Constant Coe¢ cient Homogeneeous DE. Case 1: Starting simple: Finding two Linearly independent solutions of Linear second order Constant Homogeneous DE s. Solutions to ▯ 2 ▯ 00 0 Ly = aD + bD + c y = ay + by + cy = 0: (1) Lets look at the simpler case of ▯ 2 ▯ 00 0 Ly = D + a D + 1 2 y = y + a y1+ a y 2 0: (2) 00 where the coe¢ cient of y is 1: To solve the homogeneous equation 00 0