HP HP12C hp 12c_user's guide_English_E_HDPMBF12E44.pdf - Page 180

180 Appendix B: More About L 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_user's guide_English_HDPMBF12E44 Printered Date: 2005/7/29 Page: 180 of 209 Dimension: 14.8 cm x 21 cm