For an arithmetical sequence, the first term is 2 and the common difference is 3. Find the sum of the 11 terms of the sequence.

Answer 1

f1=2, d=3
sum=n/2[2a+(n-1)d]
=11/2[2x2+(11-1)3]
=11/2[4+10x3]
= 11/2[34] = 11x17 =187

Answer 2

I dont really understand

Answer 3

Thanks but f represent what