P. G Suma de n términos

Question 1

Hallar la suma de los primeros 4 términos si r = 3 y a1 = 2

Answer 1

S4 = 80

Question 2

Hallar la suma de los primeros 6 términos si r = 2 y a1 = 5

Answer 2

S6 = 315

Question 3

7Σ3 5(2)^n-1

Answer 3

620

Question 4

4Σn=1 3(5)^n-1

Answer 4

478

Question 5

7Σi=0 (-4)^i

Answer 5

-13107