Prove that : \(\int \frac{1}{a^2 - x^2}\,dx = \frac{1}{2a}\log\left(\frac{a + x}{a - x}\right) + c\).
Q.23 Prove that : \(\int \frac{1}{a^2 - x^2}\,dx = \frac{1}{2a}\log\left(\frac{a + x}{a - x}\right) + c\).
Q.23 Prove that : \(\int \frac{1}{a^2 - x^2}\,dx = \frac{1}{2a}\log\left(\frac{a + x}{a - x}\right) + c\).
Best answer
Answer: Split \(\frac{1}{a^2 - x^2}\) into partial fractions and integrate.
\(\frac{1}{a^2 - x^2} = \frac{1}{(a + x)(a - x)} = \frac{1}{2a}\left[\frac{(a - x) + (a + x)}{(a + x)(a - x)}\right] = \frac{1}{2a}\left[\frac{1}{a + x} + \frac{1}{a - x}\right]\).
\(\int \frac{1}{a^2 - x^2}dx = \frac{1}{2a}\left[\int \frac{1}{a + x}dx + \int \frac{1}{a - x}dx\right] = \frac{1}{2a}\left[\log|a + x| - \log|a - x|\right] + c\)
\(= \frac{1}{2a}\log\left|\frac{a + x}{a - x}\right| + c\). Hence proved.
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