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BarlowGirl
PLEASE HELP!!!!! URGENT!!!! Please show steps for the attached problem . . .
Evaluate - |dw:1339003375467:dw|
I got an answer of 91, but the answer choices for the problem don't include that as an answer.
since you only have 5 terms, might as well just add them up... 4^2 + 5^2 + 6^2 + 7^2 + 8^2 + 9^2 = 16 + 25 + 36 + 49 + 64 + 81 = ???
Wait a second, though - aren't there 6 terms (4,5,6,7,8,9)? Don't you include the the k= number AND the number above sigma?
you're add k^2 so starting from k=4 to k= 9, you add 4^2 + 5^2 + ... 9^2
you should get 271 as the sum of those squares
Here's the equation for a quadratic series, in case you'd like it: |dw:1339003827921:dw|
Oh, I see what you're saying. Why doesn't the formula work for this problem, though?
that is correct.. but you'll have to subtract k=1 to k=3...|dw:1339003974534:dw|
Sorry, I'm a bit confused - what does that mean - "you'll have to subtract k=1 to k=3..." ?
so you can use that formula.... but isn't it easier to just write down those 6 terms and add them all up?
Yes, I do think it's easier, but I wanted to figure out how I could use it with the formula. I don't believe my teacher taught us to subtract the k values - that's why I'm confused.
Oh, okay. Thank you very much for your explanation! You've been most helpful! =)