règles de sommation lorsque k = 1

Question 1

sommation k =

Answer 1

n(n+1)/2

Question 2

sommation k^2

Answer 2

n(n+1)(2n+1)/6

Question 3

sommation k^3

Answer 3

[n(n+1)/2]^2

Question 4

sommation a

Answer 4

an