Wolfram Alpha
The easiest way to explain the power of the Wolfram Alpha site, I think, is to show you some examples:
Derivatives
- derivative of x4 sin x – be sure to click on "show steps"
- derivative evaluated at a point of (1 + sqrt(x))^7 at x = 4
- second derivative of sin(2x)
- implicit differentiation dy/dx for x^2 + y^2 = 1
Integrals
- an indefinite integral – be sure to click on "show steps"
- a definite integral – if you want to see the steps, make it an indefinite integral instead
Graphs
- a graphing example – if the complex parts of the graph confuse you, try adding a domain restriction
- multiple lines on the graph
The beauty of the Wolfram Alpha engine is that it's very forgiving in terms of syntax. In fact, the less you type into the search box, the more information it gives you. For example, to graph an equation, you just need to type the equation into the search box and it will automatically be plotted for you. To start using Wolfram Alpha, I recommend using one of the above links and then modifying the text in the Search Box to get the expression/equation you are interested in.
Two dangers to be aware of:
- When Wolfram Alpha outputs "log(x)", they actually mean "ln(x)" or "loge(x)".
- A lot of the graphs contain the curves for complex values of the variable as well as real.
Note: you can also branch out and ask questions like: What is the answer to life, the universe, and everything?