They cannot be because of errors that can be made by the measurer, calibration of instruments.
3 pencils to each calculator
The formula used to determine the SPARQ ratings have never been made public. Sometimes you are able to use calculators on the website to work out your scores.
It was the development and rapid popularity of electronic calculators, and then computers. Slide rules are amazing devices, but people can have nearly instant answers with any degree of accuracy desired without having to know how to do the calculations on a slide rule. And let's face it; people who used them all the time may have been quite good with them, but some of the processes were tricky and needed a little time to master.
The use of slide rules declined quickly after the introduction of inexpensive calculators. By 1976, calculators could be purchased at prices competitive with slide rules, and since their use did not require special training, they were more accurate, and they had greater functionality, it made little sense for most people to get slide rules. There are still some slide rules being manufactured for special purposes, however. One such is a circular proportional scale used for determining the size to make a copy on a copy machine according to a different size of paper from the original.
Texas Instruments
Scientific calculators can calculate numbers into scientific notation, great for earth science and chemistry class. These are made by Texas Instruments.
Yes, and Texas Instrument is located in the northern DFW area.
A graphing calculator is a scientific calculator with a graphing display window. Otherwise, there are no limits to the type of calculations that can be made on either of them.
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Marantz makes their own projectors. The DLP panel inside is made by Texas Instruments.
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Annuity calculators are used to calculate the returns on investments made in annuities.
Many companies. The first "scientific" calculators were mechanical calculators that were hand cranked and were built in the early 1920s by companies like Marchant, Monroe, and Sumlock based on their earlier business calculator designs going back to the 1880s. The main difference was that the "scientific" calculators had more digits and came with booklets giving algorithms to calculate commonly used functions needed in science and engineering (e.g. trigonometry, logarithms, roots). Electronic scientific calculators came much later (1960s to 1970s) and were also made by many companies like Hewlett Packard, Texas Instruments, Smith Corona Marchant, and Sinclair.
LM is a manufacturer's code--all LM chips were made by National Semiconductor. Similarly, SN chips were made by Texas Instruments.
There are several companies that have made microprocessors. National Semiconductor, AMD, CYRIX, Texas Instruments, and Motorola are just a few examples.
The first calculator was made in Hawaii