25 lines
493 B
TeX
25 lines
493 B
TeX
\documentclass{article}
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\input{../../../preamble}
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\newcommand{\lean}[1]{\leanref
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{./Arithmetic.html\#Real.Arithmetic.#1}
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{Real.Arithmetic.#1}}
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\begin{document}
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\section{\unverified{Sum of Arithmetic Series}}%
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\label{sec:sum-arithmetic-series}
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Let $(a_i)_{i \geq 0}$ be an arithmetic sequence with common difference $d$.
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Then for some $n \in \mathbb{N}$,
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$$\sum_{i=0}^n a_i = \frac{(n + 1)(a_0 + a_n)}{2}.$$
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\begin{proof}
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\lean{sum\_recursive\_closed}
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\end{proof}
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\end{document}
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