Evaluate: `intsqrt(x^2-9` dx

Explanation

`I=int sqrt{x^{2}-9} d x` This is of the form
`

int sqrt{x^{2}-a^{2}} d x`


We know that `int sqrt{x^{2}-a^{2}} d x=frac{x}{2} sqrt{x^{2}-a^{2}}-frac{a^{2}}{2} log |x+sqrt{x^{2}-a^{2}}|+c`

Replace `a arrow 3`
`

therefore I=frac{x}{2} sqrt{x^{2}-3^{2}}-frac{3^{2}}{2} log |x+sqrt{x^{2}-3^{2}}|+c`
`
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