Precalculus Examples

$\sum_{k = 1}^{4} 3 k$

Step 1

The formula for the summation of a polynomial with degree $1$ is:

$\sum_{k = 1}^{n} k = \frac{n (n + 1)}{2}$

Step 2

Substitute the values into the formula and make sure to multiply by the front term.

$(3) (\frac{4 (4 + 1)}{2})$

Step 3

Simplify.

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Step 3.1

Add $4$ and $1$ .

$3 \frac{4 \cdot 5}{2}$

Step 3.2

Multiply $4$ by $5$ .

$3 (\frac{20}{2})$

Step 3.3

Divide $20$ by $2$ .

$3 \cdot 10$

Step 3.4

Multiply $3$ by $10$ .

$30$