WEBVTT

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Here is the problem: integrate 1/(x squared minus 1).

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Find the indefinite integral (antiderivative) of 1 / (x squared minus 1) with respect to x.

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Start with the integral.

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Partial fractions: split 1/((x minus r₁)(x minus r₂)) into A/(x minus r₁) plus B/(x minus r₂).

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Simplify and add the constant of integration.

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So the answer is -(ln(abs(x plus 1)) / 2) plus ln(abs(x minus 1)) / 2 plus C.

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An antiderivative F satisfies F prime of x equals f(x). Because the derivative of any constant is 0, every antiderivative differs by a constant C.

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Differentiated the answer and compared it with the integrand at 8 sample points, which checks out.