Questions on the analytic and numeric equation solving functions of Mathematica (Solve, Reduce, NSolve, FindRoot, DSolve, RSolve, etc.).
6
votes
3answers
443 views
Arithmetic operation on the value returned by Solve
I want to modify the value that is returned by Solve. Example:
SolC1 = Solve[Sin[ π x / L] == 1, x]
{{x -> L/2}}
I need to add n to x so that x becomes ...
15
votes
3answers
382 views
Using results of Reduce
Suppose I have function f:
f[x_, y_] := 50000 + x 30000 + y 35000;
Now I want to find the x and y when f[]<=200000.
I use Reduce:
...
12
votes
2answers
453 views
Suppressing negative roots in Mathematica
Problem
Using Mathematica's Solve operator can sometimes lead to an output involving a positive and negative root (say when solving for a variable such as ...
7
votes
1answer
341 views
Using Mathematica to help to determine the consistency of and numerically solve systems of non-linear equations
The formal problem
The question I am about to ask is applicable to many scientific and engineering problems. In short, I am bout to ask for pointers and practical advice for Mathematica beginners who ...
7
votes
5answers
193 views
Why is FindInstance finding non-instances?
Consider this example:
FindInstance[Exists[{x, y}, x > 1 && y > 1 && x > Sqrt[x + y]], {x, y}]
which finds values of $x$ and $y$ such ...
9
votes
2answers
3k views
Figuring when the minute and hour hand coincide on a clock
I would like to list all possible times in a 12-hour period, where the hour hand overlaps the minute hand completely. This is really a question about three distinct things - to be done in Mathematica ...
31
votes
7answers
894 views
Updating Wagon's FindAllCrossings2D[] function
Stan Wagon's Mathematica in Action (second edition; I haven't read the third edition and I'm hoping to eventually see it), demonstrates a nifty function called ...
