Question

tính A= \(^{2^0+2^3+2^5+...+2^{99}}\)

Answer 1

Ta có: A = 1 + 2³ + 2⁵ +...+2⁹⁹

=> 2A = 2 + 2⁴ + 2⁶ +.....+2¹⁰⁰

=> 2A - A = ( 2+2⁴ +....+2¹⁰⁰) - ( 1+2³ + ....+2⁹⁹)

=>    A      =  2¹⁰⁰ - 1

Answer 2

A = 2⁰ + 2³ + 2⁵ + ... + 2⁹⁹

2³A = 2³ + 2⁵ + 2⁷ + ... + 2¹⁰¹

2³A - A = ( 2³ + 2⁵ + 2⁷ + ... + 2¹⁰¹ ) - ( 2⁰ + 2³ + 2⁵ + ... + 2⁹⁹ )

7A = 2¹⁰¹ - 2⁰

A = ( 2¹⁰¹ - 2⁰ ) : 7