4- Case to be studied: Don Beville invested yearly in a fund for his children's college education. At the beginning of the first year, he invested $1000; at the beginning of the second year, $2000; at the third through the sixth, $2500 each year; and at the beginning of the seventh, he invested $5000. At the beginning of the eighth year, there was $21,259 in the fund. (a) Draw a time line for this investment program. (b) Write a seventh-degree polynomial equation in 1 + i that gives the YTM for this investment program. (c) Use a graphing calculator to show that the YTM is less than 5.07% and greater than 5.05%. (d) Use a graphing calculator to calculate the solution for 1 + i and find the YTM. (e) Go to the website WolframAlpha.com, and ask it to solve the polynomial from part (b). Compare this method of solving the equation with using a graphing calculator