# Looking for a function calculator

I am looking for a calculator which can calculate functions like $f(x) = x+2$ at $x=a$ etc; but I am unable to do so. Can you recommend any online calculator?

• Check mark the first entry in Function calculator then hit the show button. – J. W. Perry Jun 23 '14 at 14:19
• Or use a spreadsheet (Microsoft or Open Office). – lemon Jun 23 '14 at 14:20
• wolframalpha.com... you can enter the expression "f(x) = x+2 at x=a" exactly as you wrote it in your question... Personally, I would rate this site as one of the most innovative websites ever created (alongside Wikipedia, Stack Overflow (or Stack Exchange in general), YouTube and Google Maps). – barak manos Jun 23 '14 at 14:30

## 3 Answers

Try the Desmos Graphing Calculator. The output looks really nice.

GeoGebra works well for this, eg http://web.geogebra.org/?command=f(x)=x+2;a=2;f(a)

You can use the Calcpad online calculator for free: Just go to http://calcpad.net/Calculator Try to type the following example into the 'Script' box:

f(x) = x + 2
a = 4
f(a)
a = 6
f(a)
\$Plot{f(x) @ x = 0 : a}


Then press 'Enter' or refresh the output to see the results