Evaluate: `int(4x+1)\ sqrt(x^2-x-2)\ dx`

Explanation

Let `I =int(4 x+1) sqrt{x^{2}-x-2} {dx} `

`4 x+1=lambda frac{d}{d x}(x^{2}-x-2)+mu `

`Rightarrow 4 x+1=lambda(2 x-1)+mu `

`Rightarrow 4 x+1=(2 lambda) x+mu-lambda`

Equating coefficient

`2 lambda=4 `

`Rightarrow lambda=2`

And

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