I need help with summation notation. Look at picture

asked Jun 20, 2021 5.5k views

1 vote

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4 votes

Answer:

=18

Explanation:

$\sum _(j=1)^33j$

Apply the constant multiplication rule:

$=3\cdot \sum _(j=1)^3j$

$\sum _(j=1)^3j$

Apply sum formula:

$=(1)/(2)\cdot \:3\left(3+1\right)$

$(1)/(2)\cdot \:3\left(3+1\right)$

$=3\cdot \:4\cdot (1)/(2)\\$

$=(1\cdot \:3\cdot \:4)/(2)$

=(12)/(2)

$=3\cdot \:6$

=18

Fcbflying answered Jun 25, 2021

4.3k points

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