Casio Fx 9700GE, Pounds 119.99 (inc VAT) Casio Electronics, Unit 6, 1000 North Circular Rd,London NW2 2JD. We are fast approaching the time when a mere scientific calculator will be regarded with the same disdain that students in secondary schools and colleges now reserve for four-function models. The past two years have seen the appearance of several good graphic calculators from companies such as Texas Instruments and Hewlett-Packard. Now from Casio comes a real competitor.
The ability to plot and analyse graphs of functions is the main reason for buying one of these calculators, so the clarity of the display is of paramount importance. Although curves on this machine, as on others, can suffer from jagged steps, its great advantage is the size of the screen which, at about 6cm by 4cm, is very easy on the eye.
The keyboard is clear and well laid out, and the cursor buttons are easy to use, although I would have preferred keys with a positive action.
The alternative functions for each key are, as is standard now, colour coded, but Casio could have made it easier for users by choosing colours further apart than orange and red. The calculator is surprisingly light, but feels well built.
When you switch on the machine, the menu is displayed in the form of icons which give you access to the main functions. If used in computation mode, the complete calculation is shown and can be easily amended with the cursor keys, thus avoiding the need to type it all in again. In graphical mode, you can choose between rectangular, polar, parametric or inequality graphs. Once drawn, a trace function moves a cursor along the curve, displaying the co-ordinates of the cursor.
Zooming in or out and choosing an area for more detailed examination, are easily accomplished using the screen menus which are controlled by the function keys. The graphs can also be displayed in a dynamic mode, showing what happens as co-efficients change value.
Graphs can be stored for later use and processes such as finding roots, intercepts or maxima and minima, are easily performed using built-in functions. The screen can be split in two, allowing you to compare an active graph with an earlier one.
Statistical processes such as bar and line graphs, the normal distribution and regression, are catered for. Integrals, matrix operations, including inversion, and the solution of linear, quadratic and cubic equations are also relatively easy with this calculator. In addition, it is possible to program it and link it to another calculator or to a computer using a separate cable.
The manual is comprehensive and full of examples, but it sometimes disconcertingly misses out a step. However, this is a machine with which you quickly feel at ease and of which Casio can feel proud.
