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Prove that ` sum_(n)^(r=0) ""^(n)C_(r)*3^(r)=4^(n).` |
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Answer» LHS=`.^(n)C_(0) xx 3^(0) + .^(n)C_(1) xx 3 + .^(n)C_(2) xx 3^(2)+...+^(n)C_(n)3^(n)` `=(1+3)^(n)=4^(n)= RHS " "` [by binomial expansion]. |
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