a) Show that the sum of the coefficients in the expansion of (a+b)^n is 2^n
b) If the sum of the coefficient in the expansion of [ 1/ (^3√x) +x√x}^n is 256, find the coefficient of x in the expansion
i would like to have the complete solution of the above questions,thanks a lot.
a.math ( binomial theorem)
2006-11-06 5:37 am
回答 (1)
2006-11-06 7:52 am
✔ 最佳答案
a) (a+b)^n = a^n+(nC1)*(a^n-1)*(b)+.....+(nCn-1)(a)(b^n-1)+b^nput a=1,b=1,
then
2^n= 1 + (nC1) + ....+ (nCn-1) + 1 = the sum of the coefficients
b) are you mis type something?? what is (^3√x) ??
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