Question

Arithmetic Question. Question in comments.

Answer 1

I just need help with D?

Answer 2

@tkhunny

Answer 3

you should fix part c

I think they want
\[ a_n = a_1 + (n-1) d \]
for the first part of C (but with your a1 and your d)

Answer 4

Yep, was just going to say that.

Answer 5

oh im so confused? It says use sigma?

Answer 6

the 2nd part is to use the sigma notation

Answer 7

so, I had the second part right? or just none?

Answer 8

the 2nd part is not correct because you have it "saying"
add up 5, 6, 7...

you should add up
\[ a_n= 4 + (n-1)\cdot 4 \]

Answer 9

if you know algebra, you can simplify
\[ a_n= 4+ 4(n-1) \\ = 4+4n - 4 \\= 4n\]
and that is what you add up (for n=1 to 10)

Answer 10

oh... so? i guess im confused as to what my answer should be them?

what am I changing?

and what is part D?