HP F2216A hp 33s_user's manual_English_E_HDPM20PIE56.pdf - Page 120

Keys: Display: Description: This value from the Y-register is the estimate made just prior to the final result. Since it is the same as the solution, the solution is an exact root. This value from the Z-register shows the equation equals zero at the root. The dimensions of the desired box are 50 × 10 × 15 cm. If you ignored the upper limit on the height (20 cm) and used initial estimates of 30 and 40 cm, you would obtain a height of 42.0256 cm - a root that is physically meaningless. If you used small initial estimates such as 0 and 10 cm, you would obtain a height of 2.9774 cm - producing an undesirably short, flat box. If you don't know what guesses to use, you can use a graph to help understand the behavior of the equation. Evaluate your equation for several values of the unknown. For each point on the graph, display the equation and press X- at the prompt for x enter the x-coordinate, and then obtain the corresponding value of the equation, the y-coordinate. For the problem above, you would always set V = 7500 and vary the value of H to produce different values for the equation. Remember that the value for this equation is the difference between the left and right sides of the equation. The plot of the value of this equation looks like this. 7500 _ (40_H) (20_H) 4H 20,000 _10 _10,000 7-10 Solving Equations H 50