## Casio fx-115 scientific calculator

The calculator.

 Casio fx-115 Brand name Casio Model number fx-115
 Logic system. Does your calculator use algebraic or RPN (reverse Polish notation) logic? How do you tell? An algebraic calculator has an = key; An RPN calculator has an ENTER key. To add two numbers (say, 2 & 3) on an algebraic calculator, you type the keys "2 + 3 =". On an RPN calculator, you type "2 ENTER 3 +".
 Casio fx-115 Algebraic or RPN? Algebraic Algebraic calculators can be further subdivided into AOS and DAL. If you know which type yours is, you can write that here. Otherwise, you will figure that out later on the form. AOS
 Shift keys. Shift keys are used to get the second (or third) function for a particular key. If there are two shift keys, list both.
 Casio fx-115 What is the label on the "shift" key(s) INV Where is the shift key? top left

Scientific notation; entering. Identify the key used to enter the exponent. (It is usually EE or EXP, or similar.)
* A special case concerns entering a number that starts with 1x in scientific notation: do you need to enter the 1? Try it... Calculate 1x1012 * 2. Do it twice, once with the first 1 and once without it. Do you need to enter the 1 to get the correct answer, 2x1012?
* The key for making an exponent negative is the same key used for entering negative numbers.

 Casio fx-115 What is the label on the key for entering exponents? EXP Where is that key? just left of = When entering a number that starts with 1x in scientific notation, do you need to enter the 1? (e.g., 1x1012) yes; must enter the leading 1 What is the key for making an exponent negative? +/- Where is that key? far left of bottom row of function keys

Scientific notation; display.

 Casio fx-115 Most scientific calculators allow you to "force" the display to use (or to not use) scientific notation. Many calculators allow you to set the number of decimal places displayed. (Some calculators also have an option for "Engineering notation", which is a variation of Scientific notation. Not important for most people.) Mode 8 sets the display to scientific notation. Mode 7 sets the display to fixed decimal notation. You must follow the Mode 8 or Mode 7 key with a single digit (0-9) specifying the number of decimal places. Examples: Mode 8 4 -- sets the display to scientific notation with four decimal places. Mode 7 0 -- sets the display to fixed decimal notation with zero decimal places.

Logarithms (and anti-logs). In intro chem we most often use base 10 logs (log10), for example with pH. The log10 is the power of 10 of the number. For example, the log10 of 1000 is 3; and then the antilog10 of 3 is 1000.
* On some calculators, you press the LOG key before the number, and on some you press the number then the LOG key.

 Casio fx-115 How is the log10 key labeled? LOG How is the base 10 antilog key labeled? 10x. It is INV LOG. To take the log10 of 1000 which do you enter first, the number or the LOG key? The number. That is, enter 1000 LOG. The preceding step serves to distinguish AOS and DAL calculators. If your calculator uses algebraic notation, and if you enter the number first, then it is AOS; if you enter the LOG first, it is DAL. The same pattern holds for other one-key functions, such as antilog and square root. Base e logs (loge or ln) are called natural logs. We do not use these in intro chem, but you are likely to use them if you go much beyond that. How are the keys labeled for natural logs and antilogs? LN anti-log: ex. It is INV LN.

Miscellaneous. These are functions we do not use in intro chem, but which you are likely to use in other math and science courses. Briefly noted here.

 Casio fx-115 Angles: degrees or radians (Some calculators also have an option for "grad". The grad is 0.9 degree, so that a right angle is 100 grad. Not commonly used.) MODE 4 sets the calculator to work in degrees; MODE 5 sets it to work in radians. Polar vs rectangular coordinates

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Main page for "Using your scientific calculator". (Links for other calculators posted here; links for other sources of information about calculators, including some possible sources for manuals.)
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