Question

Sigma Notation and the nth Term

Answer 1

Answer: F

Explanation:

1+2+...+n = n*(n+1)/2 for all natural numbers n.

Left-hand-side = (5+1)+(5+2)+...+(5+10)=5*10+10*(10+1)/2=50+55=105

Right-hand-side = (4)+(4+1)+...+(4+9)=4*10+9*(9+1)/2=40+45=85

105≠85

The equation is false