Question

sa se calculeze
1*1/2+2*(1/2)^2+...+n*(1/2)^n

Answer 1

Răspuns:

S = 1/2 + 1/2*(1/2+2*(1/2)^2+...+n*(1/2)^n)

S = 1/2 + 1/2*(1/2(1- (1/2)^n)/(1-1/2))

S = 1/2 + 1/4*(1-(1/2)^n)

S = 1/4 + 1/4*(1-(1/2)^n)

Explicație pas cu pas:

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