sir,                                                                                                       please tell me the solution of ,how can i prove that                                   2cos^2x+cos2x=6tan^2x

I think these are enough for getting a good rank. Now it all depends upon how much effort you put in towards your preparation. I would also like you to get the book named "IIT Master" from TMH which contains IIT papers and its solution of the last 25 years. I would also recommend you get ML Khanna's IIT Mathematics for mathematics and it contains many excellent problems for IIT JEE.