HP 113394 User Guide - Page 244

244 Appendix C: More About L Searching for IRR. You can continue searching for IRR solutions, even after an Error 3 indication, as follows: 1. Make a guess for the interest rate and key it in. 2. Press:gt. Your guess will aid the calculator in its search, and if it finds an IRR answer near your guess, that answer will be displayed. Since the calculator cannot tell you the number of solutions that exist when there is more than one mathematically correct answer, you can continue to make guesses, pressing :gt after each one, to search for IRR solutions. You can hasten this process by using the l function to help you make a good guess. Remember that a correct IRR solution will make the calculated NPV very small. So continue to guess interest rates and solve for NPV until the answer you obtain is reasonably close to zero. Then press :gt to calculate the IRR answer near your guess. How would this work in case 2 above? The calculator displays a negative answer and you wish to check for a unique positive IRR. Key in successively larger guesses for i (starting from 0) and solve for NPV until you reach a sign change in your NPV outcomes. Then press :gt to find an IRR solution near the last interest rate obtained using the l key. If you stop the IRR iterative process, you can test the interest obtained using l, and then restart the process by pressing :gt. File name: hp 12c pt_user's guide_English_HDPMF123E27 Page: 244 of 275 Printed Date: 2005/8/1 Dimension: 14.8 cm x 21 cm