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  "body": "\n## Summary\n\nThe Heaviside cover-up method is a quick way to find coefficients in a [[partial fraction decomposition|030VFEREKG]].\nLet $(s - a)^m$ be a factor of the denominator.\nThe coefficient of $1/(s - a)^m$ is found by deleting (\"covering up\") this factor and evaluating the rest of the fraction at $s = a$.\nWhen all roots of the denominator are simple, it gives the whole decomposition, which is why it is a standard step in inverting [[Laplace transforms|0V49JEZW06]].\n\n## Explanations\n\n### L1 human\n\nTake $\\frac{3 s + 5}{(s + 1)(s + 2)} = \\frac{A}{s + 1} + \\frac{B}{s + 2}$.\nTo find $A$, cover the factor $(s + 1)$ with your finger and put $s = -1$ in what is left: $\\frac{3(-1) + 5}{(-1) + 2} = 2$.\nTo find $B$, cover $(s + 2)$ and put $s = -2$: $\\frac{3(-2) + 5}{(-2) + 1} = 1$.\nSo the fraction is $\\frac{2}{s + 1} + \\frac{1}{s + 2}$, which one can check by adding the two terms back.\n",
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