HP 40gs hp 40gs_user's guide_English_E_HDPMSG40E07A.pdf - Page 33

hp40g+.book Page 21 Friday, December 9, 2005 1:03 AM HINT However, for clarity, it is better to include the multiplication sign where you expect multiplication in an expression. It is clearest to enter AB as A*B. Implied multiplication will not always work as expected. For example, entering A(B+4) will not give A*(B+4). Instead an error message is displayed: "Invalid User Function". This is because the calculator interprets A(B+4) as meaning 'evaluate function A at the value B+4', and function A does not exist. When in doubt, insert the * sign manually. Parentheses You need to use parentheses to enclose arguments for functions, such as SIN(45). You can omit the final parenthesis at the end of an edit line. The calculator inserts it automatically. Parentheses are also important in specifying the order of operation. Without parentheses, the HP 40gs calculates according to the order of algebraic precedence (the next topic). Following are some examples using parentheses. Entering... 45 π 45 π 85 9 85 9 Calculates... sin (45 + π) sin (45) + π 85 × 9 85 × 9 Getting started 1-21