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Prove by using the principle of mathemtical induction: ` 3.2^2 +3^2.2^3+…+3^n .2^(n+1) = 12/5 (6^n-1) ` |
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Answer» `P(k): 3*2^(2)+3^(2)*2^(3)+…+3^(k)*2^(k+1)=12/5 (6^(k)-1)`. Now, ` (3*2^(2)+3^(2)*3^(2)+…+3^(k)*2^(k+1))+3^(k+1)*2^(k+2)` ` ={12/5(6^(k)-1)+3^(k+1)*2^(k+1)*2}=1/5*{12(6^(k)-1)+10xx6^(k+1)}` ` = 1/5 *{2(6^(k+1)-6)+10 xx 6^(k+1)} = 12/5 (6^(k+1)-1)`. |
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