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Example 9 -  Find value of cos (-1710) - Chapter 3 Class 11

Example 9 - Chapter 3 Class 11 Trigonometric Functions - Part 2

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Example 9 Find the value of cos (–1710°). cos⁡(−1710°) = cos⁡(1710°) = cos⁡(1710 ×𝜋/180) = cos⁡(19𝜋/2) = cos⁡(9 1/2 𝜋 ) = cos⁡(10𝜋−𝜋/2) Value of cos x repeats after an interval of 2π, Hence, ignoring 5 × (2π) i.e. 10π = cos⁡((−𝜋)/2) = cos⁡((−180)/2) = cos⁡(–90°) = cos⁡90° = 0 As cos (−x) = cos x

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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.