Question

tinhs A = 1 + 4 + 4² + 4³ + ....... + 4⁹⁹

Answer 1

Ta có : A = 1 + 4 + 4² + ..... + 4⁹⁹

=> 4A = 4 + 4² + 4³ + ..... + 4¹⁰⁰

=> 4A - A = 4¹⁰⁰ - 1

=> 3A = 4¹⁰⁰ - 1

=> A = \(\frac{4^{100}-1}{3}\)

Answer 2

Ta có : A = 1 + 4 + 4² + ..... + 4⁹⁹

=> 4A = 4 + 4² + 4³ + ..... + 4¹⁰⁰

=> 4A - A = 4¹⁰⁰ - 1

=> 3A = 4¹⁰⁰ - 1

=> A = \(\frac{4^{100}-1}{3}\)

Answer 3

Ta có : A = 1 + 4 + 4² + ..... + 4⁹⁹

=> 4A = 4 + 4² + 4³ + ..... + 4¹⁰⁰

=> 4A - A = 4¹⁰⁰ - 1

=> 3A = 4¹⁰⁰ - 1

=> A = \(\frac{4^{100}-1}{3}\)