NCERT Resources > NCERT Class 11 > NCERT Class 11 Maths

Access Free Repository for Maths Grade 11

Access world-class FREE learning resources for grade 11 mathematics learners with which your child can touch the sky. Give them a taste of UPSC, IAS and other competitive examinations while preparing with Learner's Note's learning repository. Your child now is just a search away from building global skills, attain school-level knowledge and clear key concepts for future learning opportunities. It's time to explore our useful Grade 11 CBSE mathematics solution-inspired repository.
Navigate through the repository by searching for resources on the basis of subjects and topics. Happy learning to you!

Class 11
Maths :-NCERT Solutions - Trigonometric Functions

Page No 74:
Question 24:

Prove that cos 4x = 1 – 8sincosx


Answer:

L.H.S. = cos 4x

= cos 2(2x)

= 1 – 2 sin2 2x [cos 2A = 1 – 2 sin2 A]

= 1 – 2(2 sin x cos x)2 [sin2A = 2sin A cosA]

= 1 – 8 sin2x cos2x

= R.H.S.


NCERT Maths Class 11

SET