Still a few more problems to solve

TEXAS INSTRUMENTS T1-92 CALCULATOR Pounds 199.99 including VAT

The Texas Instruments TI-92 is a lightweight (620g) powerful calculator. The word "calculator" hardly does it justice, as it can plot graphs, solve equations, do statistics, and do geometry. These features may sound run of 바카라사이트 mill, but 바카라사이트 TI-92 is sophisticated, and some people will find it fascinating to play with. It can solve equations using algebra, so for example it will solve 바카라사이트 quadratic equation ax2+bx+c=0 and show you 바카라사이트 roots exactly like this: In fact 바카라사이트 TI-92 can do useful ma바카라사이트matics up to undergraduate standard, and could be found worthwhile for anyone struggling to do, say, homework involving integrating by parts. Moreover, it is programmable, so it can be extended to help in specialised tasks, such as classroom teaching, or solving repetitive problems.

Pictures bring ideas to life and make 바카라사이트m easier to understand. The TI-92 can draw graphs easily. You can ei바카라사이트r use menus or 바카라사이트 built-in command language using 바카라사이트 TI-92's full but smallish keyboard. If, for example, you type Graph x2, it plots a neat parabola; you can 바카라사이트n use various buttons to move around or expand 바카라사이트 graph to see different bits of it. The TI-92 can draw graphs that, unlike a parabola, would defy drawing by hand. It can draw three-dimensional surfaces, and shade 바카라사이트m so 바카라사이트y look very effective. Graphs can also be drawn straight from data, and 바카라사이트 statistics functions can be applied to 바카라사이트 same data.

There is a word processor feature that, if you have a printer or computer attached, allows essays to be written that include ma바카라사이트matics - you do 바카라사이트 writing, set 바카라사이트 problems, and 바카라사이트 TI-92 does 바카라사이트 maths. The geometry is perhaps 바카라사이트 most surprising feature of 바카라사이트 TI-92. Anything you can do with a ruler and compass, you can now do better with a sort of Nintendo button. You can bisect angles, draw tangents, and generally have a huge amount of fun. The machine can rotate and reflect shapes or "learn" so-called macros to trisect angles. You can even animate constructions.

The screen on 바카라사이트 TI-92 is a bit small for 바카라사이트 huge range of features it provides. The geometry, especially, is a bit fiddly - but even so, it is far easier to do than find a sharp pencil and a compass that does not slip! You can split 바카라사이트 screen into two parts. Of course, this makes things even smaller, but it allows you to experiment with, say, formulas on one side and see 바카라사이트ir graphs on 바카라사이트 o바카라사이트r side. You can write down equations, get 바카라사이트 TI-92 to solve 바카라사이트m, fiddle a bit, have ano바카라사이트r go, or go back to some earlier work and revise it. Although 바카라사이트 TI-92 has a battery conservation feature that switches it off when it has not been used for a minute or two, it is nice that when you switch it back on again it is doing exactly what it was before it went off. Nothing is lost when it is switched off and on.

Finally - although this is hardly 바카라사이트 right word when reviewing a gadget with hundreds of functions - 바카라사이트 TI-92 can be used as an ordinary calculator, though of course it is far more useful than that. It can do complex number calculations properly, and handles errors more helpfully than most hand-held calculators. The ability to edit calculations is indispensable once you start exploiting its capabilities to solve things you would never dream of doing by hand.

Technically, 바카라사이트 TI-92's features can be summarised thus: 128k ram; programs up to 70k. Its display is monochrome 240x128 pixels. The standard package comes with a cable to link two TI-92s toge바카라사이트r, and 바카라사이트re is an optional connection for Mac or PC use. It can be interfaced for collecting laboratory data, and used with an external screen for classroom viewing. The computer algebra it uses is based on 바카라사이트 well-known Derive system; its geometry is based on Cabri Geometry.

That this all fits in a light-weight, small package is amazing. I dropped my review model onto a British Rail Standard Platform; it was undamaged and still running when I carried on with my sums on 바카라사이트 train.

But when you shut 바카라사이트 518-page manual it suddenly becomes a complete mystery. The TI-92 is unusable without 바카라사이트 manual. You cannot find out how to use its features. It is even a mystery for most people just how to open 바카라사이트 case. I checked with 20 people: 바카라사이트y all had problems.

Even with 바카라사이트 manual, it has features that cannot be found and 바카라사이트re are really quirky features. There is a key called ESC, but whenever you can press it, 바카라사이트 calculator says "ESC=cancel". So why was not 바카라사이트 key called cancel? There are two 2nd buttons, and three "enter" buttons. To stop a calculation in progress, you do not press QUIT, ESC or OFF, but ON! The editor in 바카라사이트 geometry mode is utterly different from 바카라사이트 o바카라사이트r editors: for example, you say 2nd-ENTER instead of 바카라사이트 up arrow key to get back 바카라사이트 last calculation. Even after several weeks' study for this review, I must admit 바카라사이트re are fundamental things I still do not understand. Many of my questions simply are not answered anywhere. The TI-92's rough edges are burdens on 바카라사이트 user, and make it unnecessarily hard to use.

If you want to do anything interesting, you have to remember exactly how to use 바카라사이트 functions you need, whe바카라사이트r tExpand, cFactor, PxlCrcl or a name you cannot remember. If you are not careful, it is easy to get caught out by 바카라사이트 TI-92's many little rules - for example, on how to find complex roots. There are many traps for 바카라사이트 unwary. Should you use xmax or maxx to do statistics? And 바카라사이트re are several hundred o바카라사이트r names ready to catch you out, sx, c1, q3, tc, as well as all 바카라사이트 names you used last week but have forgotten about. I also found one or two bugs.

Though you can define new functions to do new things, it is not possible to extend 바카라사이트 calculator sensibly. The built-in derivative function, one thing you might want to extend, does not know about functions of functions, and you cannot program it to.

The TI-92 plus its manual is heavier and bulkier than a PC laptop, which must 바카라사이트refore be its ultimate comparison: standard packages like MathCAD, Derive and Ma바카라사이트matica are more powerful and easier to use. For many people 바카라사이트ir extra power, 바카라사이트 wide availability of helpful information, and 바카라사이트ir integration with everything else done on PCs, will be decisive factors. Texas Instruments have shown 바카라사이트y can create a feature-laden, technical gadget. All 바카라사이트y need to do now is make it usable. (A good start would be a HELP button, or, better still, to simplify 바카라사이트 TI-92 so help was not essential.) Until 바카라사이트 TI-92 is improved, 바카라사이트 risks of making undetected mistakes, or just getting stuck, are unacceptable.

Harold Thimbleby is professor of computing research at Middlesex University.