Is there a scientific calculator app that runs on OS X?

Question

I am looking for a scientific calculator app for Mac OS X. I don't mean anything like Matlab (or Octave, etc.), but more powerful replacement for Calculator.app.

Features should include:

• History: both input (what I entered) and output (what was the answer). Related to this, editing and re-executing old statements should be easy.
• Normal calculator functions - entering 1+1 should output 2, not just plot it.
• Drawing graphs from the functions (2D is enough, 3D is added bonus)
• All 'normal' functions, including trigonometric functions, exp, sqrt, etc.
• Quick way to enter things: it would be nice to have buttons for various functions - sin, tanh, etc., but also being able to write those directly (e.g., sin(x)*3) is almost a must.

Free is highly preferred, but cheap (less than 5€) is okay.

Answer 1

There's PCalc, a pretty powerful scriptable calculator, which is a bit difficult to get into but probably worth it. It does not, however, have any decent plotting capabilities.

Wolfram Alpha seems to meet all your needs except not having a brilliant history implementation (there IS a record of queries you have made, but it is a bit awkward to use). On the upside, it is a networked computational engine, so you will be able to obtain all kinds of information. I have been using WA for a considerable time as my calculator substitute and it has saved me the odd trip to Wikipedia for the 2011 population of Sudan or some other amazing factoid I needed. It operates as a dashboard widget, which may be a plus or a minus for you.