Question

tính tổng B=4+4^2+4^3+....+4^100

Answer 1

B = 4 + 4² + 4³ + ... + 4¹⁰⁰

4B = 4² + 4³+ 4⁴ + ... + 4¹⁰¹

4B - B = ( 4² + 4³ + 4⁴ + ... + 4¹⁰¹ ) - ( 4 + 4² + 4³ + ... + 4¹⁰⁰ )

3B = 4¹⁰¹ - 4

B = \(\frac{4^{101}-4}{3}\)

Answer 2

B= 4+4²+4³+...+4¹⁰⁰

4B=4+4²+4³+4⁴+...+4¹⁰¹

4B-B=(4+4²+4³+4⁴+...+4¹⁰¹)-(1+4+4²+4³+...+4¹⁰⁰)

3B=4¹⁰¹-1

B= 4¹⁰¹ - 1 : 3 

Answer 3

ta có B = 4 +4^2+4^3+...+4^100

4B = 4^2 +4^3+4^4+...+4^101 

4B-B = 4^101-4

3B = 4^101-4

B=(4^101-4): 3

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