1. I am not able to see the animations in the section "Mathematics- With Animations"?

There can be two reasons.

1. You have to download latest Java from http://www.java.com/en/ . The animations are java applications using Geogebra which requires java.

2. It takes some time to download the .jar file of the application onto your temporary memory (thats what i think) and you will see something like this on the screen (see the right pic)