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whatevs

  • 3 years ago

Need help on thiss

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  1. whatevs
    • 3 years ago
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  2. FoolForMath
    • 3 years ago
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    -28

  3. whatevs
    • 3 years ago
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    how did you solve it...i have 5 more problems like this..

  4. whatevs
    • 3 years ago
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    is there a way to put it into wolfram?

  5. FoolForMath
    • 3 years ago
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    I looked at it then I thought of a number.

  6. FoolForMath
    • 3 years ago
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    http://www.wolframalpha.com/input/?i=Sum%5B-2+n+%2B+4%2C+%7Bn%2C+4%2C+7%7D%5D

  7. whatevs
    • 3 years ago
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    can you help me with these kind of problems?

  8. FoolForMath
    • 3 years ago
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    Sure.

  9. whatevs
    • 3 years ago
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    Given the sequence 9, 12, 15, which of the following is equivalent to

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  10. whatevs
    • 3 years ago
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    thanks aloot..

  11. mathmate
    • 3 years ago
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    You can split the summations, and evaluate each one separately. \[\sum_{4}^{7}-2n+4 = \sum_{4}^{7}-2n + \sum_{4}^{7}4\] \[= -2\sum_{4}^{7}n + 4\sum_{4}^{7} 1\] \[= -2(\sum_{1}^{7}n - \sum_{1}^{3}n ) + 4(4)\] \[= -2[ 7(7+1)/2 - 3(3+1)/2 ] - 16\] \[= -44 + 16\] \[= -28\]

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spraguer (Moderator)
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is replying to Can someone tell me what button the professor is hitting...

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