hey sandeep,

dont even dare to mug up the derivations !!

rather try to remember the basic formulae!!

& try to find appliction of this formulae in the right place.

well, to say the truth  names of various books on identity wont help u to score high unless u can develop your logic but if u r in urgent need of the names of the books then i tell u M.L. Khanna , Asit Dasgupta  , Das, Mukherjee on Trigonometry & Arihant will really turn up for u.

but for the basic development of the logic u can follow R.D . SHARMA.

HOPE THIS WILL REALLY HELP U.

IF I AM OF ANY HELP THEN PLZZZZZZZZ... DO RATE ME !!!!!