PLEASE!!!!!!!!!! I don't know how to do Sigma sums!!!?

Question

1.100
∑ (3k²-5k)
k=1

2. n
∑ k k+1)(k+2)
K=1

3.100
∑ f(i/100)(1/100), where f(x)=4-x²
i=1

Answer 1

i did these years ago and do not remember everything that there is but i can help with the first one: take 3k^2-5k for k=1,2,3,4,5.....100 and add hem all together. i know there is an easier way but i do not remember it. sorry, i hope this info helps a little

Answer 2

The first two series do not converge, The only way I can think to get the answer is to actually do the sums, which means (in case 1) computing 3k^2-5k 100 times for k=1 to 100 and adding up the result. Very tedious by hand, but using Excel I get the result 989800.

Similarly for the case 3, each term is (4-i^2/100^2)/100 and the sum for 100 terms is 3.66165.

Sorry that's all I can contribute