(3+2n+1)/2*n=168,(n+2)*n=168,n=12
3+5+7+9.+(2n+1)=168,n=?
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相关问题
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3+5+7+.+(2n+1)=168 n=
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3+5+7…+(2n+1)=168 n=?
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3+5+7+...+(2n+1)=168则n=?
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若n为正整数,3+5+7+……+(2n+1)=168,则n=?
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1+2+3+4+5+6+7+8+9+…+n=n(n+1)/2 1+3+5+7+9+11+13+15+…+(2n-1)=n
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1+3+5+7+9+.+(2n-1)+(2n+1)+(2n+3)=
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1+3+5+7+9+.+(2n-1)+(2n+1)=
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求和:Sn=(1/3*5)+(1/5*7)+(1/7*9)+...+[1/(2n+1)(2n+3)]
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1/1*5+1/3*7+1/5*9+.+1/(2n-1)(2n+3)
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(2n-9)(2n-7)/(2n+5)(2n-3)