Ta'rif
UlashishNatural qator
A₁=1, d=1 bo'lgan progressiya. (2)-formula bo'yicha: Sₙ=(2·1+(n−1)·1)/2·n=(n+1)/2·n=153, bundan n²+n−306=0, kvadrat tenglamani yechib n=17 (musbat ildiz) ni olamiz.
Matematika · 9-sinf · Arifmetik progressiyaning dastlabki n ta hadi yig'indisi
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