Search for: If in the expansion of (a−2b)n,the sum of 4th and 5th term is zero, then the value of ab is If in the expansion of (a−2b)n,the sum of 4th and 5th term is zero, then the value of ab is An−45Bn−32C5n−4D52(n−4) Fill Out the Form for Expert Academic Guidance!l Grade ---Class 1Class 2Class 3Class 4Class 5Class 6Class 7Class 8Class 9Class 10Class 11Class 12 Target Exam JEENEETCBSE +91 Preferred time slot for the call ---9 am10 am11 am12 pm1 pm2 pm3 pm4 pm5 pm6 pm7 pm8pm9 pm10pm Please indicate your interest Live ClassesBooksTest SeriesSelf Learning Language ---EnglishHindiMarathiTamilTeluguMalayalam Are you a Sri Chaitanya student? NoYes Verify OTP Code (required) I agree to the terms and conditions and privacy policy. Solution:Here,T4=nC3(a)n−3(−2b)3and T5=nC4(a)n−4(−2b)4Given T4+T5=0⇒ nC3(a)n−3(−2b)3+nC4(a)n−4(−2b)4=0⇒ (a)n−4(−2b)3anC3+nC4(−2b)=0⇒ ab=2nC4 nC3=2⋅n(n−1)(n−2)(n−3)4⋅3⋅2⋅1×3⋅2⋅1n(n−1)(n−2)=n−32 Related content Appreciation Words Wave Optics Mind Map Alternating Current Mind Map for Class 12, JEE & NEET Paramedical Courses After Class 10 Top Courses After 12th Science with PCM, PCB and PCMB Subject Change Application in School and College CBSE Class 10 Result 2024: Is the Release Date Early? Check Expected Schedule Mizoram NEET Merit List 2023 Government Jobs After 12th Arts Stream Chhattisgarh NEET UG Merit List 2023