Example 7 - Chapter 8 Class 11 Binomial Theorem (Deleted)
Last updated at Jan. 29, 2020 by Teachoo
Last updated at Jan. 29, 2020 by Teachoo
Transcript
Example 7 Find the coefficient of x6y3 in the expansion of (x + 2y)9. We know that General term of expansion (a + b)n is Tr+1 = nCr an–r br For (x + 2y)9, Putting n = 9 , a = x , b = 2y Tr + 1 = 9Cr (x)9 – r (2y)r = 9Cr (x)9 – r . (y)r . (2)r We need to find coefficient of x6 y3 Comparing yr = y3 r = 3 Putting r = 3 in (1) T3+1 = 9C3 x9 – 3 . y3 . (2)3 = 9!/3!(9 −3 )! x6 . y3 . (2)3 = 9!/(3! 6!) (2)3 x6 y3 = (9 × 8 × 7 × 6!)/(3 × 2 × 1 × 6!) × 8 . x6 y3 = (9 × 8 × 7 × 8 )/(3 × 2) x6 y3 = 672 x6 y3 Hence coefficient of x6 y3 is 672
Examples
Example 2 Important Deleted for CBSE Board 2022 Exams
Example 3 Important Deleted for CBSE Board 2022 Exams
Example 4 Deleted for CBSE Board 2022 Exams
Example 5 Important Deleted for CBSE Board 2022 Exams
Example 6 Important Deleted for CBSE Board 2022 Exams
Example 7 Deleted for CBSE Board 2022 Exams You are here
Example 8 Important Deleted for CBSE Board 2022 Exams
Example 9 Deleted for CBSE Board 2022 Exams
Example 10 Important Deleted for CBSE Board 2022 Exams
Example 11 Important Deleted for CBSE Board 2022 Exams
Example 12 Deleted for CBSE Board 2022 Exams
Example 13 Important Deleted for CBSE Board 2022 Exams
Example 14 Important Deleted for CBSE Board 2022 Exams
Example 15 Important Deleted for CBSE Board 2022 Exams
Example 16 Deleted for CBSE Board 2022 Exams
Example 17 Important Deleted for CBSE Board 2022 Exams
Examples
About the Author