To find the sum of the first 10 terms of the sequence defined by an = 4n + 3, we first need to calculate the individual terms.
Let’s calculate the first 10 terms:
- a1 = 4(1) + 3 = 7
- a2 = 4(2) + 3 = 11
- a3 = 4(3) + 3 = 15
- a4 = 4(4) + 3 = 19
- a5 = 4(5) + 3 = 23
- a6 = 4(6) + 3 = 27
- a7 = 4(7) + 3 = 31
- a8 = 4(8) + 3 = 35
- a9 = 4(9) + 3 = 39
- a10 = 4(10) + 3 = 43
Now we can sum these terms:
Sum = a1 + a2 + a3 + a4 + a5 + a6 + a7 + a8 + a9 + a10 = 7 + 11 + 15 + 19 + 23 + 27 + 31 + 35 + 39 + 43
Calculating this step-by-step gives:
- 7 + 11 = 18
- 18 + 15 = 33
- 33 + 19 = 52
- 52 + 23 = 75
- 75 + 27 = 102
- 102 + 31 = 133
- 133 + 35 = 168
- 168 + 39 = 207
- 207 + 43 = 250
Therefore, the sum of the first 10 terms is 250.