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86d333ee94
* chore: Switch to Node 20 + Vitest * chore: migrate to vitest mock functions * chore: code style (switch to prettier) * test: re-enable long-running test Seems the switch to Node 20 and Vitest has vastly improved the code's and / or the test's runtime! see #1193 * chore: code style * chore: fix failing tests * Updated Documentation in README.md * Update contribution guidelines to state usage of Prettier * fix: set prettier printWidth back to 80 * chore: apply updated code style automatically * fix: set prettier line endings to lf again * chore: apply updated code style automatically --------- Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com> Co-authored-by: Lars Müller <34514239+appgurueu@users.noreply.github.com>
39 lines
1.3 KiB
JavaScript
39 lines
1.3 KiB
JavaScript
/*
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Returns the sum of a geometric progression
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Article on Geometric Progression: https://en.wikipedia.org/wiki/Geometric_series
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Examples:
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> sumOfGeometricProgression(2, 0.5, 6)
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3.9375
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> sumOfGeometricProgression(0.5, 10, 3)
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55.5
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> sumOfGeometricProgression(0.5, 10, Infinity)
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Error: The geometric progression is diverging, and its sum cannot be calculated
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*/
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/**
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*
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* @param {Number} firstTerm The first term of the geometric progression
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* @param {Number} commonRatio The common ratio of the geometric progression
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* @param {Number} numOfTerms The number of terms in the progression
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*/
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function sumOfGeometricProgression(firstTerm, commonRatio, numOfTerms) {
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if (!Number.isFinite(numOfTerms)) {
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/*
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If the number of Terms is Infinity, the common ratio needs to be less than 1 to be a convergent geometric progression
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Article on Convergent Series: https://en.wikipedia.org/wiki/Convergent_series
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*/
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if (Math.abs(commonRatio) < 1) return firstTerm / (1 - commonRatio)
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throw new Error(
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'The geometric progression is diverging, and its sum cannot be calculated'
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)
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}
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if (commonRatio === 1) return firstTerm * numOfTerms
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return (
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(firstTerm * (Math.pow(commonRatio, numOfTerms) - 1)) / (commonRatio - 1)
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)
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}
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export { sumOfGeometricProgression }
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