Question

Find the arithmetic sum without directly adding the terms: 20 on top of E thing 1 under then (-4i+2)

Answer 1

\[\sum_{i=1}^{20}(-4i+2)\]

Answer 2

ya mean this E thing

Answer 3

@CoconutJJ yes, i couldn't figure out how to type it

Answer 4

That is a sigma notation. Keep that in mind as it will be very helpful to know its name :).

Answer 5

\[\sum_{k=0}^{n-1}(a+kd)=\frac{ n }{ 2 }(2a+(n-1)d)\]

Answer 6

a= first term
d= common difference
n= number of terms to add up