What is the sum of all the coefficients in # (1+x)7# binomial expansion?

1 Answer
Ratnaker Mehta
Aug 5, 2017

# 2^7=128.#

Explanation:

Knowing that, the Expansion of #(1+x)^7,# is a poly. of degree #7,#

suppose that,

#(1+x)^7=a_0+a_1x+a_2x^2+...+a_7x^7....(star).#

Note : We can actually expand #(1+x)^7,# but we don't need that.

# :. x=1,#

#rArr 2^7=a_0+a_1+a_2+...+a_7"=the desired sum of the co-effs."#

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