Search for: The most general solution of21+|cosx|+cos2x+cos3x+…=4 is given byThe most general solution of21+|cosx|+cos2x+cos3x+…=4 is given byAx=nπ±π3,n∈ZBz=2nπ±π3n∈ZCx=2nπ±2π3,n∈ZDnone of these 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:The given equation is not meaningful for |cosx|=1. So, let |cosx|≠1.Now, 21+|cosx|+cos2x+|cosx|3+…+tosx=4⇒ 121−|cosx|=22⇒ 11−|cosx|=2⇒ 2−2|cosx|=1⇒ |cosx|=12⇒ cosx=±12⇒ cosx=cosπ3,cosx=cos2π3⇒ x=2nπ±π3,x=2nπ±2π3,n∈Z⇒ x=2nπ±π3,x=(2n±1)π±π3⇒ x=nπ±π3,n∈Z.Post navigationPrevious: The number of values of k for which the system of equations: (k+1)x+8y=4k,kx+(k+ 3)y=3k-1 has no solution, is Next: If 16sinx,cosx,tanx are in G.P., then r is equal toRelated content JEE Main 2023 Session 2 Registration to begin today JEE Main 2023 Result: Session 1 NEET 2024 JEE Advanced 2023 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