The problem is to evaluate the summation $\sum_{i=4}^{30} 4i$.

ArithmeticSummationSeriesArithmetic SeriesSigma Notation
2025/4/14

1. Problem Description

The problem is to evaluate the summation i=4304i\sum_{i=4}^{30} 4i.

2. Solution Steps

We need to find the sum of the terms 4i4i as ii ranges from 4 to
3

0. We can factor out the constant 4 from the summation:

i=4304i=4i=430i\sum_{i=4}^{30} 4i = 4 \sum_{i=4}^{30} i
The sum of the first nn integers is given by the formula:
i=1ni=n(n+1)2\sum_{i=1}^{n} i = \frac{n(n+1)}{2}
We can rewrite the summation from i=4i=4 to 3030 as:
i=430i=i=130ii=13i\sum_{i=4}^{30} i = \sum_{i=1}^{30} i - \sum_{i=1}^{3} i
Using the formula for the sum of the first nn integers, we have:
i=130i=30(30+1)2=30(31)2=15(31)=465\sum_{i=1}^{30} i = \frac{30(30+1)}{2} = \frac{30(31)}{2} = 15(31) = 465
i=13i=3(3+1)2=3(4)2=6\sum_{i=1}^{3} i = \frac{3(3+1)}{2} = \frac{3(4)}{2} = 6
Therefore,
i=430i=4656=459\sum_{i=4}^{30} i = 465 - 6 = 459
Now, we multiply this by 4:
4i=430i=4(459)=18364 \sum_{i=4}^{30} i = 4(459) = 1836

3. Final Answer

1836