HP 40gs hp 40gs_user's guide_English_E_HDPMSG40E07A.pdf - Page 192

hp40g+.book Page 10 Friday, December 9, 2005 1:03 AM ALGB menu COLLECT DEF 14-10 For example, suppose you have stored the expression x2 in G, and have defined the function F(x) as x2. Suppose now you want to calculate INTVX(X2). You could: • enter INTVX(X2) directly, or • enter INTVX(G), or • enter INTVX(F(X)). Note that you can apply the command directly to an expression or to a variable that holds an expression (the first two cases above). But where you want to apply it to a defined function, you need to specify the full function name, F(X), as in the third case above. Factors over the integers COLLECT combines like terms and factors the expression over the integers. Example To factor x2 - 4 over the integers you would type: COLLECT(X2-4) which gives in real mode: (x + 2) ⋅ (x - 2) Example To factor x2 - 2 over the integers you would type: COLLECT(X2-2) which gives: x2 - 2 Define a function For its argument, DEF takes an equality between: 1. the name of a function (with parentheses containing the variable), and 2. an expression defining the function. DEF defines this function and returns the equality. Computer Algebra System (CAS)