I was recently in the market for a new scientific/graphing calculator as well and decided on a Texas Instruments TI-89.
I have been using it for about 2 months now and have been extremely impressed with its usability, extensive range of functions and most of all its ability to do symbolic manipulation, differential and integral calculus and matrices.
It is approximately the same form factor as the HP-48S, but it isn't a RPN calculator. It is pretty reasonably priced at $225 Canadian (approx. $169 US).
The Mathematics system is upgradable and programs can be downloaded to the unit. There are also quite a few user groups out on the web. Such as these guys and these guys
Symbolic manipulation for algebra, calculus and differential equations.
Real and complex numeric results.
Symbolic manipulation for algebra, calculus and differential equations.
About 188K bytes of user-available RAM.
About 639K bytes of user-available FLASH ROM for user data archive and/or Handheld.
Electronic upgradability of operating system including maintenance and feature upgrades.
Pretty Print shows equations and results with radical notation, stacked fractions, and superscript exponents.
Active Calculator Home history screen can hold up to 99 previous entries for deep recall.
Real and complex numeric results.
Symbolic units for use in equations, computations, and unit conversions. Over 100 units in 28 unit categories. 20 constants with symbolic units.
Graphs functions, parametric and polar equations, recursively-defined sequences, 3-dimensional surfaces, and differential equations. Up to 99 graphing equations defined and saved for each graphing mode.
Interactive analysis of function values, roots, maximums, minimums, integrals, derivatives, intersections, inflection points, and arc lengths.
Recursively-defined sequences access any number of previous terms.
Slope and direction fields for exploring differential equations. RK and Euler numeric differential equation solving methods.
Real time rotation of 3D surfaces.
List-based one- and two-variable statistical analysis, including eight regression models.
Statistics plots including scatter, xy-line, box and modified box plots. Histograms and regression lines.
Matrix operations including inverse, determinant, transpose, augment, elementary row operations, and reduced row echelon form. Matrix elements can be real or complex and numeric or symbolic.
Advanced matrix operations including eigenvalues, eigenvectors, LU and QR decompositions.
Column-logic expressions in data/matrix editor are retained for automatic recalculation when values change.
Interactive numeric equation solver.
Hexadecimal and binary operations and conversions.
Extensive programming capability with number and size of programs limited only by available memory. User-definable functions extend built-in functionality.
Optional assembly language programming.
Command catalog screen to access and show "help" information for each function and command.
Memory management to create folders for specific applications or subjects.
255 symbols in the character set including Greek, system, and international characters.
Link capabilities for data transfer through I/O port.
Powered by 4 AAA batteries with lithium battery backup to protect memory during main battery change.
There is already a known effect called Cerenkov Radiation that is due to massed particles travelling faster than the speed of light in a particular medium.
This is possible when light is travelling through some medium like water, where the speed of light is lower than light in a vacuum. The charged massed particles excite the atoms of the medium and the excited particles return to their normal state by emitting a photon.
This is the effect that causes reactor cores to glow.
I don't beleive that it is a direct analogy to a sonic boom, but I thought it may be interesting none the less.
Percontor
Slashdot Mirror
I was recently in the market for a new scientific/graphing calculator as well and decided on a Texas Instruments TI-89.
I have been using it for about 2 months now and have been extremely impressed with its usability, extensive range of functions and most of all its ability to do symbolic manipulation, differential and integral calculus and matrices.
It is approximately the same form factor as the HP-48S, but it isn't a RPN calculator. It is pretty reasonably priced at $225 Canadian (approx. $169 US).
The Mathematics system is upgradable and programs can be downloaded to the unit. There are also quite a few user groups out on the web. Such as these guys and these guys
Here is a link to the page on the TI site about the TI-89.
Here are some of its features:
Symbolic manipulation for algebra, calculus and differential equations.
Real and complex numeric results.
Symbolic manipulation for algebra, calculus and differential equations.
About 188K bytes of user-available RAM.
About 639K bytes of user-available FLASH ROM for user data archive and/or Handheld.
Electronic upgradability of operating system including maintenance and feature upgrades.
Pretty Print shows equations and results with radical notation, stacked fractions, and superscript exponents.
Active Calculator Home history screen can hold up to 99 previous entries for deep recall.
Real and complex numeric results.
Symbolic units for use in equations, computations, and unit conversions. Over 100 units in 28 unit categories. 20 constants with symbolic units.
Graphs functions, parametric and polar equations, recursively-defined sequences, 3-dimensional surfaces, and differential equations. Up to 99 graphing equations defined and saved for each graphing mode.
Interactive analysis of function values, roots, maximums, minimums, integrals, derivatives, intersections, inflection points, and arc lengths.
Recursively-defined sequences access any number of previous terms.
Slope and direction fields for exploring differential equations. RK and Euler numeric differential equation solving methods.
Real time rotation of 3D surfaces.
List-based one- and two-variable statistical analysis, including eight regression models.
Statistics plots including scatter, xy-line, box and modified box plots. Histograms and regression lines.
Matrix operations including inverse, determinant, transpose, augment, elementary row operations, and reduced row echelon form. Matrix elements can be real or complex and numeric or symbolic.
Advanced matrix operations including eigenvalues, eigenvectors, LU and QR decompositions.
Column-logic expressions in data/matrix editor are retained for automatic recalculation when values change.
Interactive numeric equation solver.
Hexadecimal and binary operations and conversions.
Extensive programming capability with number and size of programs limited only by available memory. User-definable functions extend built-in functionality.
Optional assembly language programming.
Command catalog screen to access and show "help" information for each function and command. Memory management to create folders for specific applications or subjects.
255 symbols in the character set including Greek, system, and international characters.
Link capabilities for data transfer through I/O port.
Powered by 4 AAA batteries with lithium battery backup to protect memory during main battery change.
Hope this helps.....
Percontor
For reference see:
http://www.hrvg.org/project/erminmink/reactor/ce renkov.htm
This is possible when light is travelling through some medium like water, where the speed of light is lower than light in a vacuum. The charged massed particles excite the atoms of the medium and the excited particles return to their normal state by emitting a photon. This is the effect that causes reactor cores to glow. I don't beleive that it is a direct analogy to a sonic boom, but I thought it may be interesting none the less. Percontor