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Prove the following by using the principle of mathematical induction for all `n in N`:`(1+3/1)(1+5/4)(1+7/9)dotdotdot(1+((2n+1))/(n^2))=(n+1)^2` |
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Answer» `" Let "P(n) : (1+3)(1+(5)/(4))(1+(7)/(9))` `......(1+(2n+1)/(n^(2)))=(n+1)^(2)` For n=1 `L.H.S. =1+3 =4,R.H.S. =(1+1)^(2)=4` `:. L.H.S. =R.H.S.` `rArr` P (n) is true for n=1 Let P (n) be true for n=K. `P(k) :(1=3)(1+(5)/(4)) (1+(7)/(9))` `......(1+(2k+1)/(k^(2))) =(k+1)^(2)` For n=K+1 `P(k+1) : (1+3) (1+(5)/(4)) (1+(5)/(9))` `......(1+(2K+1)/(k^(2))).{1+(2(k+1)+1)/((k+1))}` `=(k+1)^(2) {1+(2(K+1)+1)/((K+1)^(2))}` `=(k+1)^(2){((k+1)^(2)+2(K+1)+1)/((k+1)^(2)]}` `={(K+1)+1}^(2)=(K+2)^(2)` `rArr` P (n) is also frue for n=K+1 Hence from the principle of the mathamatical induction P (n) is true for all natural numbers n. |
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