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Selected answers to common questions:
- Dates that Read the Same Backwards and Forwards [02/02/2010]
A student sees a palindrome in the date 01 02 2010, and wonders how to
generate all such palindromic dates. Building on another math doctor's
work with date arithmetic, Doctor Carter shares a program written in C,
then goes on to explain the purpose of each line of code.
- Decimal To Fraction Conversion - A Simpler Version [11/25/2002]
A simpler version of the algorithm.
- Definition of Floating Point Data [07/02/2001]
What are 'floating point data'? How do they differ from an integer? What
are some examples?
- Determining File Compression Ratio [04/11/2001]
What equation will find compression ratio regardless of the time it took
- Displaying Large Repetends on Small Calculators [05/31/2002]
How can I find a 16-digit repetend using an 8-digit calculator?
- EE Key on a Calculator [10/25/1999]
What does "EE" on the calculator stand for?
- Equivalence Relations [08/12/2003]
If I have a function that maps from R to R (where R is the reals) and
a set of functions, say O(f), for g where there exist constants c and
a in R+ (positive reals), where |g(x)| is less than or equal to c|
f(x)| for x greater than a, how would I define a relation, say Q, on
the set of functions mapping R to R by putting (g,h) in R iff g-h is
- Erlang B [10/22/2002]
I need to know how to calculate the addition of numbers using
logarithms: 1 + 2 + 3. There is a step that requires adding numbers
that exceed Excel's limits. How can I use logs to add the numbers?
- Exact Answers for Square Roots [04/16/2006]
My teacher says that one of the problems with using calculators is
that you don't always get exact answers. I don't understand why.
Aren't calculators accurate?
- Exponents on a Scientific Calculator [08/21/1997]
My problem is that I am not using the EXP key correctly...
- Expressing Arccos in Terms of Arctan [02/24/1997]
How do you express Arccos in terms of Arctan?
- Fabric Left on a Roll [03/15/2001]
I am going to write a program for my TI-83+ to calculate how many feet of
material are left on a roll.
- Factorial on TI-83 [09/24/1997]
What is the origin of the TI-83 definition of factorial (in increments of
0.5) and where is it used? What resources would you suggest?
- Finding All Combinations of Numbers [07/23/2002]
Programs in C++ and Visual Basic for finding all possible combinations
of numbers using a pre-defined set.
- Finding an Angle [08/09/2002]
I need to know how to calculate an angle between two points.
- Finding Percentages on a Calculator [06/22/2006]
How does the percent key on a calculator work? How do I use it to find
a percent of a number?
- Finding Pi in C++ [10/10/2001]
I want to write a program in C++ to find the first 100 digits in Pi
following the sequence: 4-(4/3)+(4/5)-(4/7)+...
- Finding Roots on a Calculator [04/22/2001]
How can I use the equation HPR = (1.667)^(1/5) on a calculator that does
not have a fifth root key?
- Floating 2 [06/12/2001]
Start with the number 2 on the far left side, then float the number 2 to
the far right side; the new number must be three as large as the old
- Fraction Algorithm [03/19/2002]
I have been having trouble making an application that can convert a
finite decimal to a fraction without doing 78349/1000000.
- Games for TI Calculators [6/6/1995]
Where can I find programs for a TI-82 calculator?
- Generating Permutations With a Computer [06/20/2002]
I want to write a computer program to solve 'Jumble' word puzzles.
- Generating Permutations With a Computer [06/20/2002]
I have a friend named REBECCA. How can I generate all the
distinguishable permutations of all the letters of her name?
- Generating Random Numbers [02/24/2001]
Would you know of any congruential models for the generation of random
- Generating Random Numbers with Specified Probabilities [08/10/2003]
Given an evenly distributed Pseudo Random Number (PRN) generator (with
each generated outcome having the same probability), how can I
generate outcomes with specified probabilities?
- Graphing Peculiarity [07/24/2002]
When I use a calculator to graph one form of an equation it works
fine; but when I use a different form, it doesn't work. What's going
- High School Math Software [7/12/1996]
Where can I get good shareware/freeware programs that deal with high
school math topics?
- History of Writing Decimals and Number Lines [10/28/1998]
Why, on a number line, are the negative numbers are on the left? When you
deal with decimals, why are the whole numbers are on the left?
- How a Calculator Determines Values of Trig Functions [03/19/2005]
I'm interested in how my calculator finds the answer of sin(pi/4) or
tan(pi/6), for example. Does it use power series?
- How a CPU Adds Decimal Numbers [10/22/2000]
How does an 8-bit CPU add up two four-digit decimal numbers, and why does
it take four operations to do so?
- How Many Triangles? [10/30/2001]
If we join one point on each of the three sides of a triangle to make
another triangle, there are three triangles with vertices pointing up.
How many triangles will have vertices pointing up if there are n points?
- HP-38G Graphic Calculator [08/29/1998]
I'm having trouble graphing on my HP-38G calculator. Can you help?
- Implied Multiplication and TI Calculators [05/02/2008]
If I type 36/6(25-11*2) into my TI-85, I get an answer of 2. If I
include a multiplication symbol to have 36/6*(25-11*2), I get an
answer of 18. I thought that when the 6 is written right up against
the parenthesis, the multiplication is implied. Why am I getting two
- Integer Modulus vs. Remainder [03/14/2002]
We were taught by our computer professors that the modulus is the
remainder of an integer division, but your discussion leads me to believe
this is not quite true.
- Interpreting 2^3^2 [04/26/2001]
Why is 2^3^2 interpreted as 2^(3^2) = 512 instead of (2^3)^2 = 64?
- Introduction to Fractals [09/02/1998]
Can you give me some basic information on fractals? How would you create
- Inverse Sine Function on a Calculator [5/14/1996]
Finding Arcsin(y) using a calculator.
- Julian to Calendar Date Conversion [02/24/2001]
Can you show me an algorithm to convert Julian date values to calendar
date values? For example, Julian date 2451964 = 02/24/2001.
- KaleidoTile [11/15/1995]
I would appreciate it if you would tell me a bit about KaleidoTile.
- Large Prime Numbers [12/17/1997]
Is there an algorithm to determine whether a very large number is prime?