How do I write this as an expanded sum ? :?

4 ( )

∑ ( 2i² - 1 )

i = 1 ( )

1 Answer

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  • sparky
    Lv 4
    9 years ago
    Favorite Answer

    start by replacing the "i" in the expression (2i² - 1) with 1, then 2, then so on until you get to 4. The start value and end value are indicated below and above the summation sign (and are called the lower and upper index of summation)

    ( 2(1)² - 1 ) + ( 2(2)² - 1 ) + ( 2(3)² - 1 ) + ( 2(4)² - 1 )

    or: 1 + 7 + 17 + 31 if you simplify the terms

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