Wolfram Book 之等比数列的前 n 项和

例 1

Mathematica 代码:

a[n_] := a1 q^(n – 1);

Solve[{a[1] + 8 a[4] == 0, r == Sum[a[i], {i, 4}]/Sum[a[i], {i, 3}]}, {r, q}, Reals]

例 2

Mathematica 代码:

a[n_] := a1 q^(n – 1);

Solve[{a[3] == 2 (a[1] + a[2]) + 1,

a[4] == 2 (a[1] + a[2] + a[3]) + 1, q != 0}, {a1, q}]

例 3

Mathematica 代码:

a[n_] := a1 q^(n – 1);

Minimize[{a[1] + a[2] + a[3] + a[4] + a[5] + a[6], a[1] + a[2] + a[3] + a[4] == 2 (a[1] + a[2]) + 1, q > 1}, {a1,q}] // Simplify

发布者:Cara,转载请注明出处:http://www.makercollider.com/course/1747

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