As derivations are not asked in JEE so you can learn the result of them instead of learning the whole derivation.

Which is the toughest subject in JEE?

Which is the toughest subject in engineering? If we look into the past years papers of JEE Main and JEE Advanced, it is mostly seen that the difficulty level of Physics is the highest followed by Math.

Are trigonometric proofs important for JEE?

Trigonometric Identities & Equations is a vital topic of IIT JEE Trigonometry syllabus. ... The topic of Trigonometric identities is also important as it fetches some direct questions in JEE on the basis of formulae.