Search for: If A+B+C=3π2,then cos2A+cos2B+cos2C is equal toIf A+B+C=3π2,then cos2A+cos2B+cos2C is equal toA1−4cosAcosBcosCB4sinAsinBsinCC1+2cosAcosBcosCD1−4sinAsinBsinC 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:Since,A+B+C=3π2∴cos2 A+cos2B+cos2C =2cos(A+B)cos(A−B)+cos2C =2cos3π2−Ccos(A−B)+1−2sin2C =1−2sinCcos(A−B)+sin3π2−(A+B) =1−2sinC[cos(A−B)−cos(A+B)] =1−4sinAsinBsinCPost navigationPrevious: The value of sin12∘sin48∘sin54∘ is equal toNext: If xcosθ=ycosθ+2π3=zcosθ+4π3,then the value of 1x+1y+1z is equal to Related content 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 JEE Advanced Crash Course – JEE Advanced Crash Course 2023