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Ex 8.2
Ex 8.2, 2 Important Deleted for CBSE Board 2022 Exams
Ex 8.2, 3 Deleted for CBSE Board 2022 Exams
Ex 8.2, 4 Important Deleted for CBSE Board 2022 Exams
Ex 8.2,5 Deleted for CBSE Board 2022 Exams You are here
Ex 8.2 6 Important Deleted for CBSE Board 2022 Exams
Ex 8.2,7 Deleted for CBSE Board 2022 Exams
Ex 8.2,8 Important Deleted for CBSE Board 2022 Exams
Ex 8.2,9 Deleted for CBSE Board 2022 Exams
Ex 8.2,10 Important Deleted for CBSE Board 2022 Exams
Ex 8.2,11 Important Deleted for CBSE Board 2022 Exams
Ex 8.2,12 Deleted for CBSE Board 2022 Exams
Ex 8.2
Last updated at Jan. 29, 2020 by Teachoo
Ex 8.2, 5 Find the 4th term in the expansion of (x – 2y)12 . We know that General term of expansion (a + b)n is Tr+1 = nCr an–r br We need to find fourth term i.e. T4 = T3 + 1 of expansion (x – 12y)12 Putting r = 3 , a = x , b = –2y , n = 12 T3 + 1 = 12C3 (x)12 – 3 (–2y)3 = (12 !)/(3! (12 − 3)!) x9 (–2)3 (y)3 = 12!/(3! × 9!) x9 (–8) y3 = (12 × 11 × 10 × 9!)/(3 × 2 × 9 !) × (–8) × x9 y3 = (12 × 11 × 10 × (−8))/6 × x9 y3 = 2 × 11 × 10 × (–8) × x9 y3 = –220 × 8 x9 y3 = –1760 x9 y3