Introduction to Series (2 of 2: Constructing Sigma Notation)

[@samwhite7717]

Why am I so engrossed in your teachings, damn it! Thank you so much, Eddie.

[@alexbenyiu5216]

Best online video teacher!

[@anime-bw7vq]

thank you so much

[@hal-soormediafans748]

Teacher let me explain, where is come from (2n-1). How to get that?

[@moose3471]

its the formula for arithmetic sequences

[@moose3471]

for the n'th unit

[@k4w4iilover]

Eddie said whatever the difference is between the terms, in this case 2 (9-7=2, 7-2=5, etc), you make that the coefficient of n and then add or subtract to get the first term. So because the difference is 2, make it the coefficient of n= 2*n and given 3 is our first n term, we get 2*n= 2*3 which gives 6. Because we want 5, subtract 1: 6-1 = 5. And you can see this works for n = 4 as well. 2*n will be 2*4 = 8 and then subtract 1: 8 -1 = 7. I hope this helps somewhat.