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What is the sum of the series?

[tex]\[ \sum_{k=1}^4 \left(2 k^2 - 4\right) \][/tex]

Enter your answer in the box.

[tex]\[ \square \][/tex]


Sagot :

To find the sum of the series [tex]\(\sum_{k=1}^4 (2k^2 - 4)\)[/tex], we will evaluate the expression term by term and then sum the results.

Let's break it down step by step:

1. Evaluate the expression for [tex]\( k = 1 \)[/tex]:
[tex]\[ 2(1)^2 - 4 = 2 \cdot 1 - 4 = 2 - 4 = -2 \][/tex]

2. Evaluate the expression for [tex]\( k = 2 \)[/tex]:
[tex]\[ 2(2)^2 - 4 = 2 \cdot 4 - 4 = 8 - 4 = 4 \][/tex]

3. Evaluate the expression for [tex]\( k = 3 \)[/tex]:
[tex]\[ 2(3)^2 - 4 = 2 \cdot 9 - 4 = 18 - 4 = 14 \][/tex]

4. Evaluate the expression for [tex]\( k = 4 \)[/tex]:
[tex]\[ 2(4)^2 - 4 = 2 \cdot 16 - 4 = 32 - 4 = 28 \][/tex]

Next, we sum these individual results:
[tex]\[ -2 + 4 + 14 + 28 \][/tex]

Now, add these values together:
[tex]\[ -2 + 4 = 2 \][/tex]
[tex]\[ 2 + 14 = 16 \][/tex]
[tex]\[ 16 + 28 = 44 \][/tex]

Therefore, the sum of the series [tex]\(\sum_{k=1}^4 (2k^2 - 4)\)[/tex] is
[tex]\[ \boxed{44} \][/tex]