www.wolframalpha.com
simply wow.
its a bit slow but wow. simply wow. really dose give you the answers.
i typed in: ln(x^2 +5) =
in the search box and got ****loads graphs as well as several ways of solving it including the equations derivative, series expansion, the integral, global minimum etc.
its a bit slow atm and seems to crash now and again but wow
edit: just did x^4(1-x)^-3 and it gave me the derivative, the integral...the graph..
although it failed to integrate 2xe^x^2