cbse12 − Q & A

Beside NCERT books, which would be the best side book for 11th & 12th grade mathematics as well as Chemistry ? Plz suggest those books which are really very conceptual and understandable.

Find the general solution of Cos theta.cos2theta.cos 3theta =1/4

Do in CBSE, besides mathematics, step-markings available to physics & chemistry numericals and biology answers ?

Are gel pens allowed in Class-12th Board Exam in CBSE ? & which ink colour should be used for writing the same? Someone said me that black colour is prohibited. Is it really so?