WolframAlpha - A Computational Knowledge Search Engine

A student at my school let me know about a computational search engine called WolframAlpha. The goals of this search engine are ambitiously laid out as follows:

Wolfram|Alpha's long-term goal is to make all systematic knowledge immediately computable and accessible to everyone. We aim to collect and curate all objective data; implement every known model, method, and algorithm; and make it possible to compute whatever can be computed about anything. Our goal is to build on the achievements of science and other systematizations of knowledge to provide a single source that can be relied on by everyone for definitive answers to factual queries.
Wolfram|Alpha aims to bring expert-level knowledge and capabilities to the broadest possible range of people—spanning all professions and education levels. Our goal is to accept completely free-form input, and to serve as a knowledge engine that generates powerful results and presents them with maximum clarity.
Wolfram|Alpha is an ambitious, long-term intellectual endeavor that we intend will deliver increasing capabilities over the years and decades to come. With a world-class team and participation from top outside experts in countless fields, our goal is to create something that will stand as a major milestone of 21st century intellectual achievement.

The people at WolframAlpha are associated with Mathematica, a powerful math software package. I performed a search with WolframAlpha to have it compute the derivative of 2 + 6sin^2 (0.3t). It correctly gave me 3.6sin (0.3t)cos (0.3t). It also provided me with graphs of the derivative and other information.

This might be a great tool for math students.