Search for: The number of values of x lying in the internal (−π,π) which satisfy the equation 81+|cosx|+cos2x+cos3x+…∞=43,is The number of values of x lying in the internal (−π,π) which satisfy the equation 81+|cosx|+cos2x+cos3x+…∞=43,is A3B4C5D6 Register to Get Free Mock Test and Study Material +91 Verify OTP Code (required) I agree to the terms and conditions and privacy policy. Solution:Now,1+|cosx|+cos2x+cos3x+…∞=11−|cosx|∴ 811−|cosx|=43⇒31−|cosx|=26⇒1=2−2|cosx|⇒|cosx|=12⇒cosx=±12⇒x=π3,−π3,2π3,−2π3∴ Number of solutions =4Post navigationPrevious: The sum of the following series 1+6+912+22+327+1212+22+32+429+1512+22+…+5211+… upto 15 terms, isNext: Let a, b and c be the 7th’ 11th and 13th terms respectively of a non-constant A.P, If these are alsothe three consecutive terms of a G.P., then ac=Related content NEET Rank Assurance Program | NEET Crash Course 2023 JEE Main 2023 Question Papers with Solutions JEE Main 2024 Syllabus Best Books for JEE Main 2024 JEE Advanced 2024: Exam date, Syllabus, Eligibility Criteria JEE Main 2024: Exam dates, Syllabus, Eligibility Criteria JEE 2024: Exam Date, Syllabus, Eligibility Criteria NCERT Solutions For Class 6 Maths Data Handling Exercise 9.3 JEE Crash Course – JEE Crash Course 2023 NEET Crash Course – NEET Crash Course 2023