For part a and b I was able to compute i* using the quadratic equation but I am not familiar on how to calculate using interpolation. In addition, I am not sure how Goal See works, whereas I know we can get the IRR using excel simply by typing in IRR. Is Newton's method the same thing as the quadratic formula for part C? And what does it mean by plotting PW against i? Is there a formula for ERR for part d?

EDIT: Ignoring goal seek, is how is the best way to do the rest of the problem?

2. Park Problem 7.15: Consider the following sets of investment projects: A D 10 -$150 -$180 -$50 -$280 -$80 $60 $220 $70 $20 $-100 1 2 $900 $70 $10 $40 $-50 $40 $5 $40 $0 4 $40 $-180 $-20 $150 $150 5 $60 $40 $50 $100 $30 $40 7 $100 8 $30 $20 10 $10 a) Classify each investment as either simple or non-simple b) Compute i* for Project A, using the quadratic equation, for Project B using interpolation. Confirm your answer using EXCEL's Goal Seek LO LO c) Identify all positive is for Projects C, D, and E using a numerical method (e.g. Newton's method) Confirm your answers by plotting PW against i d) For Project C, find the external rate of return ERR assuming that the external reinvestment rate and borrowing rate are equal to MARR of 8%, i.e. e 8%. 2. Park Problem 7.15: Consider the following sets of investment projects: A D 10 -$150 -$180 -$50 -$280 -$80 $60 $220 $70 $20 $-100 1 2 $900 $70 $10 $40 $-50 $40 $5 $40 $0 4 $40 $-180 $-20 $150 $150 5 $60 $40 $50 $100 $30 $40 7 $100 8 $30 $20 10 $10 a) Classify each investment as either simple or non-simple b) Compute i* for Project A, using the quadratic equation, for Project B using interpolation. Confirm your answer using EXCEL's Goal Seek LO LO c) Identify all positive is for Projects C, D, and E using a numerical method (e.g. Newton's method) Confirm your answers by plotting PW against i d) For Project C, find the external rate of return ERR assuming that the external reinvestment rate and borrowing rate are equal to MARR of 8%, i.e. e 8%