find the coefficient of xn in the expansion of(1+x)(1-x)n
Answers
Answered by
1
Need homework help? Click here.
Coefficient of xn in (1+x)(1−x)n=1× coeff. of xn in (1−x)n+1× coeff. of xn−1 in (1−x)n
∴ Coefficient of xn in (1+x)(1−x)n=(−1)nnCn+(−1)n−1nCn−1
=(−1)n[1−n]
Coefficient of xn in (1+x)(1−x)n=1× coeff. of xn in (1−x)n+1× coeff. of xn−1 in (1−x)n
∴ Coefficient of xn in (1+x)(1−x)n=(−1)nnCn+(−1)n−1nCn−1
=(−1)n[1−n]
Similar questions