Search for: A be the sum of the first 20 terms and B be the sum of the first 40 terms of the series 12+2⋅22+32+2⋅42+52+2⋅62+….…If B−2A=100λ, then λ is equal to A be the sum of the first 20 terms and B be the sum of the first 40 terms of the series 12+2⋅22+32+2⋅42+52+2⋅62+….…If B−2A=100λ, then λ is equal to A496B232C248D464 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:Let S=12+2⋅22+32+2⋅42+52+2⋅62+…The sum of first 20 terms isA=12+22+….+202+22+42+….+202=20⋅21⋅416+4⋅10⋅11⋅216=20⋅216(41+22)=4410B=12+2⋅22+….+2⋅402 =12+22+….+402+22+42+….+402 =40⋅41⋅816+4⋅20⋅21⋅416=33620B−2A=33620−8820=24800∴ 100λ=24800⇒λ=248 Related content Female Reproductive System Diagram Class 10 NCERT Solutions for Class 11 English Reading Skills Chapter 1 The Portrait of a Lady 50+ Simple GK Questions and Answers for Class 8 Animal Cell Diagram Class 9 Preparation Strategy for NEET Repeaters CBSE Power Sharing Class 10 MCQs Political Science Chapter 1 How to Self Study for NEET Dropper at Home? CBSE Class 9 English Wind Worksheet Viram Chinh in Hindi Worksheets Class 9 with Answers MP Board Class 8 Result 2024 – MPBSE Class 8 Result (Out)