Question

HELP WITH SIGMA NOTATION pleas

Answer 1

@robtobey @imqwerty

Answer 2

Hi

Answer 3

What in particular is confusing you about this?

Answer 4

\[\sum_{3}^{12}(-5n-1)=-16-21-26-...-61\]
a=-16
d=-5
n=10
\[Sn=\frac{ n }{ 2 }\left( a+l \right)=\frac{ 10 }{ 2 }\left( -16-61 \right)=?\]

Answer 5

5*-77=?

Answer 6

ah so thats it?

Answer 7

thank you that was really helpful, I finally get it!

Answer 8

all are negative terms and sum of them will be negative also.