Web Calculator 0

by brettfo Sat, 30 Jun 2012 4:55 pm EDT

Category:

Education

Tags:

Last Updated:

2012-06-30

Current Version:

1.0.0

Requires Root:

Developer:

brettfo

Distribution:

Available via Repository

Total Downloads:

Description

Expression evaluator

The expression evaluation part of the calculator should be easy enough to figure out; you give it an expression an it'll evaluate it if possible. Some examples include:
3+4*2 -> 11 (notice that order of operations are observed)
4! -> 24
2^3 -> 8
sqrt(4) -> 2

Note that I also define 2 constants, e and pi that evaluate to exactly what you think they should. The rest of the evaluator should be easy enough to pick up with the exception of the sum() function: I wanted a way to compute summations so the arguments to this function seem a little odd at first. As an example, consider one of the many methods of approximating the natural constant e: the sum of the quantity one divided by x factorial, with x from zero to (some upper bound.) This could be entered like:
sum(1/x!,x,0,10)
and will yield 2.7182818011463845
Note that the variable x in this case is arbitrary. I could do the same thing with the variable taco:
sum(1/taco!,taco,0,10)

Graphing

Switching into the graphing mode via the button up top will show an empty graph. Simply enter any function with x as the independent variable and hit the equals sign to see the graph. Simple as that. When many graphing calculators draw a function with a vertical asymptote such as 1/x or tan(x) they will accidentally draw a vertical line where the graph really shouldn't have one. I've made what I think to be a pretty good effort at avoiding these anomalies.