4. Use Euler's method with h = 0.1 to approximate the function value f (1.5) to 3 decimal places, where f (x) is the solution to the DE dy xty dx y , y(1.1) = 1. 5. (a) Let a1 = ?' 1 r = -4. List the first 5 terms of the geometric sequence. b) Let a3 = 2, r = 2. Find the as and an for the geometric sequence