HP 40gs HP 39gs_40gs_Mastering The Graphing Calculator_English_E_F2224-90010.p - Page 345

Example 4: Factorizing expressions If you highlight an expression such as (2x+3)4 and press ENTER then the CAS will expand the bracket. Since the result extends beyond the screen we will scroll through it using the arrow keys. The results can be factorized again using the COLLECT function. In this example we will also illustrate the use of the CAS History to fetch a previous calculation. The sequence of keys for this is... Expansion... 2 +3 4 Examination... - 35 ENTER Note: Alternatively you can press and scroll through the result in the view screen. This is equivalent to the command in the HOME screen. Factorization... Press until the entire polynomial is highlighted (or press SHIFT ). While the required expression is highlighted, fetch the COLLECT function from the menu. ENTER ENTER Note: Firstly, remember that the extent of the highlight plays a very important role. Only the highlighted section of the polynomial will be included in the COLLECT brackets. This allows partial factorizations if desired. In this case the entire expression should be highlighted before COLLECT is inserted. Secondly, when ENTER is pressed the evaluation is done on whatever is highlighted. It is necessary for the entire expression, including COLLECT, to be highlighted if it is to be evaluated. If nothing is highlighted then the entire screen is evaluated. 345