9 of 9 people found the following review helpful
5.0 out of 5 stars
Not perfect, but best I've ever seen, June 30, 2005
This review is from: HP 49G+C FRENCH CANADIAN GRAPHING CALCUL (Electronics)
If you buy an HP 49G+ get one with ROM Version 1.23 or 2.0; 49G+ calculators with earlier ROM versions have minor flaws that have since been fixed.
The 49G+ is a serious graphing and programmable calculator that can be used not only by students, but by professionals with real problems to solve. Its accuracy is outstanding, although not perfect for all functions. For +, -, *, / and sqrt() on reals it delivers results accurate to 1/2 unit in the last place, rounded to nearest; overflow and underflow are determined after rounding and postnormalization. (However, it does not support gradual underflow.) Accuracy of elementary functions is excellent; e.g. it gets cos(42781604.0) correct to 12 digits correctly rounded, which is better than many large computers do. All values of n! are likewise correct to 12 digits correctly rounded. y^x gives excellent but not perfect accuracy; for integer n, y^n can be computed to any desired accuracy with the built-in integer arithmetic of the 49G+. Symbolic integrals and derivatives are outstanding. Eigenvalues, eigenvectors, and roots of polynomials are ok, provided the matrix for eigenvalues/eigenvectors is not too large, and provided eigenvalues (or roots of polynomials) are not of too high multiplicity or too closely spaced; if they are, the user can write a program to do better in the particular case to be solved.
The only serious error I have discovered in the 49G+ is an error in computation of certain confidence intervals, an error that is present in the formulas in every statistics handbook and elementary text on statistics. One can hardly blame HP for failing to discover a 60-year-old error that's repeated in all the literature.
Various excellent user-written libraries are available, and can be downloaded via a PC through a connector and software provided with the calculator, to add things like Bessel and Hankel functions that are not built in. With an added (inexpensive) ROM, up to 64 MB of such libraries can be stored in the calculator.
This calculator is obviously not the equivalent of either a major math package for large fast computers, such as Mathematica, or a specialized package for particular caluculations such as linear programming. However, it fits nicely in a pocket, and is therefore extremely useful both for calculation while on the move, and for trying algorithms while thinking through problems.
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