what is the sum of the first 10 terms of the sequence defined by ^an=2n-3?
I assume we have .....
an = 2n -3
The first term =a1 = 2(1)-3 = -1
And the 10th term = a10 = 2(10) - 3 = 20 - 3 = 17
And the sum of the first 10 terms = 10(a1 + a10)/2 = 10(-1 + 17)/2 = 5(16) = 80