# 004 Sample Final A, Problem 7

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Given a sequence use formulae on the back page to compute

Foundations |
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1) What is the formula for the nth term of an arithmetic sequence? |

2) What is the formula for the sum of the first n terms of an arithmetic sequence? |

Answer: |

1) The nth term of an arithmetic sequence is where is the first term of the sequence and is the common difference. |

2) The sum of the first n terms of an arithmetic sequence is . |

Solution:

Step 1: |
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The first term in the arithmetic sequence is and the common difference is . |

Step 2: |
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The 20th term of this sequence is . |

Step 3: |
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The sum of the first twenty terms is . |

Final Answer: |
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