HP 39g hp 39g & 40g_user's manual_English_E_pdfbpia5212.pdf - Page 91

3. Use the Plot view to find an initial guess for T. First set appropriate X and Y ranges in the Plot Setup. Since we have an equation, X = V × T + A × T2 ⁄ 2 , the plot will produce two graphs: one for Y = X and one for Y = V × T + A × T2 ⁄ 2 . Since we have set X = 30 in this example, one of the graphs will be Y = 30 . Therefore, make the YRNG -5 to 35. Keep the XRNG default of -6.5 to 6.5. SETUP-PLOT 5 35 4. Plot the graph. 5. Move the cursor near the positive (right-side) intersection. This cursor value will be an initial guess for T. to move cursor to the intersection. The two points of intersection show that there are two solutions for this equation. However, only positive values for x make sense, so we want to find the solution for the intersection on the right side of the y-axis. 6. Return to the Numeric view. Note: the T-value is filled in with the position of the cursor from the Plot view. 7. Ensure that the T value is highlighted, and solve the equation. Solve aplet 7-9