Geogebra

I like Geogebra input bar. It allows you to type equations with more than one variable. I was trying to do this with Sketchpad but could not figure a way. I tried to use the sample activity "analytic conics" on the learning center web page, but it would not work with this one particular equation, 16x^2-94x+9y^2-342y-24xy+1324=0. It should plot a parabola opened up on a diagonal toward the 1st quadrant. In Geogebra, all I had to do was to type in the equation without any necessary manipulations. The only thing is you need to place an asterisk for multiplication between the two variables x and y.

Another neat thing about Geogebra, you can type in a word in the input bar and it will find it for you. Such as the parabola above, I wanted to find its focus. I typed in the word focus and the letter assigned to that equation into the brackets and it gave me the coordinates of the focus. I did the same to find the directrix and it gave me the equation for its directrix. I don't think Sketchpad is set up to work with conic sections as fluently as Geogebra.