请问,划红线的这一步骤是怎么推算出来的呢?谢谢解答
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lim(n->∞) ∑(i:1->n) 1/[ n + (i+1)^2/n ]
=lim(n->∞) (1/n) .∑(i:1->n) 1/[ 1 + (i+1)^2/n^2 ]
=lim(n->∞) (1/n) .∑(i+1 :0->n-1) 1/[ 1 + (i+1)^2/n^2 ]
=lim(n->∞) (1/n) .∑(u :0->n-1) 1/[ 1 + (u/n)^2 ]
=∫(0->1) dx/(1+x^2)
=[arctanx]|(0->1)
=π/4
=lim(n->∞) (1/n) .∑(i:1->n) 1/[ 1 + (i+1)^2/n^2 ]
=lim(n->∞) (1/n) .∑(i+1 :0->n-1) 1/[ 1 + (i+1)^2/n^2 ]
=lim(n->∞) (1/n) .∑(u :0->n-1) 1/[ 1 + (u/n)^2 ]
=∫(0->1) dx/(1+x^2)
=[arctanx]|(0->1)
=π/4
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