Evaluate cos 48°  cos 42° − sin 48° sin 42°

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Note : This is similar to Ex 8.3, 2 (ii) of NCERT – Chapter 8 Class 10

Check the answer here https://www.teachoo.com/1774/531/Ex-8.3--1---Evaluate-(i)-sin-18---cos-72-(ii)-tan-26-cot-64/category/Ex-8.3/

  1. Class 10
  2. Solutions of Sample Papers for Class 10 Boards

Transcript

Question 24 (OR 2nd question) Evaluate cos 48° cos 42° − sin 48° sin 42° cos 48° cos 42° – sin 48° sin 42° = cos (90 – 42)° cos (90 – 48)° – sin 48° sin 42° = sin 42° sin 48° – sin 48° sin 42° = 0 (cos (90 – θ) = sin θ )

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Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.