Question

S2
=2^0+2^1+2^2+...+2^10

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Answer 1

Răspuns:

2^11 - 1

Explicație pas cu pas:

S = 2^0+2^1+2^2+...+2^10 | x2

2S = 2^1+2^2+...+2^10+2^11

2S = (2^0+2^1+2^2+...+2^10)-2^0+2^11

2S = S - 1 + 2^11

2S - S = 2^11 - 1

S = 2^11 - 1

Answer 2

$\it \dfrac{..}{..}\ \ S_n=b_1\cdot\dfrac{q^n-1}{q-1}\\ \\ \\ Din\ enun\c{\it t} \Rightarrow\ b_1=2^0=1,\ \ \ q=2\\ \\ \\ S_{11}=\dfrac{2^{11}-1}{2-1}=2^{11}-1$