Standardized "Intuitive" Operationīy moving to a standardized menu interface, the calculator became much more intuitive.
Hp financial calculators 18c plus#
The solver provided all the functions of the calculator for defining equations plus a few more features, such as conditionals which were embedded in expressions like: IF(conditional_expression:true_expression:false_expression). Each equation was added to a list so to use an older equation, the user simply scrolled to it. The number of equations and the number of variables was limited only by total memory. This would leave the display looking like: To determine the nominal rate needed to produce a real rate of return of 12% in an 8% inflation environment, the user could enter: 12 REAL, 8 INFL and then press NOM. The user would then press CALC and the HP-18C would display the equation and label the soft keys REAL, NOM, and INFL. If the isolation method failed, it used an iterative numerical approach.įor example, the user might press SOLVE and then enter an expression relating real rate of return (REAL) to the nominal interest rate (NOM) and the inflation rate (INFL):ġ + (REAL/100) = (1+(NOM/100)) / (1+(INFL/100)) If this was successful, it calculated and displayed the result. The solver worked by first attempting algebraic manipulation on the equation to isolate the unknown variable. When equations were entered, the solver automatically showed their variables on soft-keys. The calculator automatically performed the task of isolating the variable to solve for. The HP-18C introduced a powerful new solver which was as easy to use as a TVM solver yet could solve arbitrary equations like a root finder. In order to solve an equation, the user was required to manually isolate the unknown variable and enter an appropriate function to solve for it. These solvers were much more flexible than TVM solvers because they could solve any equation but they were not nearly as easy to use.
Hp financial calculators 18c software#
This first appeared as software for early HP scientific calculators and then was later built-in to models such as the HP-34C. The second kind of solver was the root finder. For unknowns, the corresponding key was pressed without first pressing a number. For each known value, the user entered the number and then pressed the corresponding key (N, I, PMT, PV or FV). This was a very easy to use solver that allowed the user to specify the known values of TVM problems and solve for unknowns. The first type was the dedicated Time Value of Money (TVM) solver that first appeared on the HP-80. Two kinds of solvers existed on earlier HP calculators.
Most of the calculator's capabilities were accessed by a single MAIN key that displayed the top menu. This allowed the calculator to provide a menu system for the majority of the advanced functions. For the first time, soft keys were labeled by the calculator itself using the high-resolution dot-matrix display rather than using cards or overlays. HP responded by providing twice as many keys and also soft keys. HP learned in focus groups that most business calculator customers disliked keyboards with many labels and shift keys. The LAST key retrieved the value on the next level of the stack into the current expression.
Though it was an algebraic machine, it had a four level "history stack" with ↑ (roll up) and ↓ (roll down) keys. (For example: 5×(2+3 would show on the display until the ) was pressed which would leave 5×5 on the display.) The calculator used algebraic logic with parentheses (but no precedence) and the multi-line display showed what was happening at all times. The calculator was based on a Saturn architecture CPU.
The HP-18C was also the first calculator to be programmed by HP in the new RPL language and it is listed in the RPL family here because of this however, this language was not made available to users of the calculator.
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