Friends this site are usefull in education you can read any topic briefly by asking this site this site has lots of information there are too many teachers which upload a video on this site when I am in 11th and 12th standard of science faculty it helps me lot more I am not take any tuition
Classes because they have higher fee but from this app I see a video related to my topic and understand it clearly their are IIT teachers which understand you via video the page of this site also uploafd quickly
Thanks for viewing