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Selected answers to common questions:
- Remaining Confusion [09/10/2011]
A programming student wonders where she has gone wrong interpreting modulus
among the order of operations. Doctor Peterson shows how to proceed, offering up
three ways to evaluate the remainder, before anticipating (correctly, it turns out) where
the student might have erred.
- Repeated Square Roots and Logarithms [04/05/2005]
A discussion based on a calculator trick where taking 'n' repeated
square roots of 'a', then subtracting 1 and multiplying by 'b', then
adding 1 and squaring 'n' times, leads to a result very close to a^b.
The explanation is closely related to logarithms.
- Repeating Decimals [04/28/1999]
I am interested in finding longer repeating groups in number tails of
- Resources on 3D Surface Plots [9/12/1995]
I would appreciate it if you would let me know of any databases or
handbooks on the Internet for 3D surface plots of equations z=f(x,y,...).
- Reverse Polish Notation [06/26/2002]
Where does the name 'Reverse Polish Notation' come from?
- Reverse Polish Notation in Calculators [09/17/2005]
An introduction to "reverse Polish notation" and the terms "stack",
"push", and "pop" in that context.
- Rolling a Die 600 and 5000 Times [06/03/2001]
Toss a die 600 times, 5000 times. How many times does each number come
up? Approximately how many would you expect?
- Software for High School Math [8/26/1996]
Do you know of any software available for helping a 15 year-old with
areas she has trouble with [algebra, geometry etc...]?
- Solving Linear Equations in Computer Programs [02/13/2003]
What is the best and simplest method in computer programs for solving
linear equations: Cramers method; Gaussian Elimination method; Inverse
- Subtraction Using Nine's and Ten's Complements [05/27/2000]
How does subtraction using the "method of complements" work? Why does it
give the correct answer all of the time?
- Summation Notation for TI86 [10/29/2001]
I was wondering if there was an easier way to do our assignment on a
- Sum of Unit Fractions [07/17/2001]
By induction, prove that every proper fraction p/q with p less than q can
be written as a finite sum of distinct reciprocals of positive integers.
- Synthetic Division on the HP48 [09/11/1997]
I read that you have a program for synthetic division for the HP48. I was
wondering if you could send it to me?
- System-Level Programming and Base 2 [05/03/2001]
In computer programming, I have a result that contains several values,
always a power of 2 (2^2, 2^3, 2^4). If my value is 2^3, 2^4, 2^6 304,
how can I tell if 2^3 exists in 304?
- Teaching Rounding Rules [10/17/2002]
I was taught that when one rounds numbers like 3.5 or 4.5 to the
nearest even integer, so that 3.5 should be rounded up, and 4.5 should
be rounded down. Is there any good reason why grade-schoolers are
taught to always round up?
- Theta Notation: Complexity and the Step Function [02/05/2001]
What does the Greek letter theta mean in this formula?
- TI-86 Base Conversion Program [03/19/2002]
I have finished writing a program that can convert any number in any base
(one-ten) to base ten. Now I am writing a program to convert any number
in base ten to a given base.
- Trig Functions in Forth [04/07/2003]
I am writing a program in the language Forth. I need to determine the
two missing angles in a right triangle...
- Trig Functions of Angles Expressed in Degrees and Minutes [05/04/1998]
Using calculators to evaluate trigonometry functions of angles expressed
in degrees and minutes.
- Twenty or Fewer Steps [08/28/2002]
Only the 1, +, -, x, /, (, ), and = keys on a scientific calculator
are working. How can a result of 75 be reached by pushing these
keys fewer than 20 times?
- Two's Complement [07/13/1999]
What is two's complement and how is it used?
- Twos Complement Notation [12/17/2001]
How to make a 2-byte negative; where in the 16 bits the sign bit is
place, and why.
- Use 10 Digits in 2 Fractions that Add to 1 [05/26/2003]
Obtain a sum of the form xx/xxx + xx/xxx = 1, using all digits 0-9
- Using a Computer to Make and Print a Scatterplot [11/23/2003]
Is there a way to use a computer to enter data and get a printout of a
scatterplot so that I don't have to do it by hand?
- Using TI's Equation Solver [09/27/1999]
How can I use the TI-82 equation solver to solve equations like x-9=0,
2x=0, and 3x-6=0?
- Ways to Make Change for $1.00 [10/02/1997]
Are there really 292 ways to make change for $1.00?
- What are Flops? [02/25/2001]
What are flops, as relating to computers?
- What Does EE Stand For? [01/14/2003]
What does the EE stand for on a scientific calculator?
- What is a Keystroke Sequence? [07/30/2002]
What is a 'keystroke sequence'?
- What is ASCII? [12/19/2000]
What is ASCII and how does it relate to binary?
- What is a Terabyte? [03/24/2002]
What is a terabyte? I know a gigabyte is one billon bytes.
- What is Modulus? [06/06/2001]
I have used the mod command and know what the results mean, but I don't
understand the theory behind it and what is actually happening.
- What's 'Arccos'? [06/17/2001]
I'm trying to write a program in Visual Basic 6 about the distance
calculation between two cities.
- Why Don't Calculators Accept (-2)^(2/3)? [02/17/2002]
If you punch (-2_^(2/3) into a scientific calculator, it gives an error
message. Could you explain why?
- Why Isn't a Kilobyte 1,000 Bytes? [03/29/2001]
If the prefix kilo- means 1000, why is a kilobyte 1024 bytes instead of
- Working with Huge Numbers [05/15/1999]
How can I work out a number such as 4 to the 300 billionth power?
- Writing an Arcsin Function in C++ [04/17/2002]
I have to write a function that computes the arcsin of an input.
- Writing a Program to Generate Primes [12/5/1996]
I need a list of the first 100 prime numbers and a way of generating
- Writing a TI-82 Program [02/20/1998]
How can I write a program that will solve quadratic equations on my TI-82
- XOR Operation [01/23/2001]
An explanation and a few examples of the XOR operation.