44 lines
1.4 KiB
Markdown
44 lines
1.4 KiB
Markdown
# Difference Of Squares
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Find the difference between the square of the sum and the sum of the squares of the first N natural numbers.
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The square of the sum of the first ten natural numbers is
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(1 + 2 + ... + 10)² = 55² = 3025.
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The sum of the squares of the first ten natural numbers is
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1² + 2² + ... + 10² = 385.
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Hence the difference between the square of the sum of the first
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ten natural numbers and the sum of the squares of the first ten
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natural numbers is 3025 - 385 = 2640.
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* * * *
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For installation and learning resources, refer to the
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[exercism help page](http://exercism.io/languages/ruby).
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For running the tests provided, you will need the Minitest gem. Open a
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terminal window and run the following command to install minitest:
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gem install minitest
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If you would like color output, you can `require 'minitest/pride'` in
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the test file, or note the alternative instruction, below, for running
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the test file.
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Run the tests from the exercise directory using the following command:
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ruby difference_of_squares_test.rb
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To include color from the command line:
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ruby -r minitest/pride difference_of_squares_test.rb
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## Source
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Problem 6 at Project Euler [http://projecteuler.net/problem=6](http://projecteuler.net/problem=6)
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## Submitting Incomplete Solutions
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It's possible to submit an incomplete solution so you can see how others have completed the exercise.
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