Q. Evaluate the integral and express your answer in simplest form.∫xx2−1−3dxAnswer:
Recognize standard form: Recognize the integral as a standard form. The integral ∫xx2−1−3dx can be recognized as a standard form related to the inverse hyperbolic function, specifically the inverse hyperbolic secant function, because the denominator has the form of a hyperbolic identity. We can use the substitution u=x2−1 to simplify the integral.
Perform substitution: Perform the substitution.Let u=x2−1, then du=2xdx. We need to express −xx2−13dx in terms of u and du. Since du=2xdx, we can write dx=2xdu. Also, since u=x2−1, we have x2−1=u.
Rewrite in terms of u: Rewrite the integral in terms of u.Substituting the expressions from Step 2 into the integral, we get:∫xu−3⋅2xduThis simplifies to:∫2u−3du
Integrate with respect to u: Integrate with respect to u.The integral of −2u3 with respect to u is a standard form. We can integrate it directly:∫(−2u3)du=−23∫u1duThe antiderivative of u1 is 2u, so we have:−23×2u+C
Simplify the result: Simplify the result.Simplifying the expression from Step 4, we get:−3u+C
Back-substitute u: Back-substitute u with x2−1.Now we need to replace u with our original substitution, u=x2−1, to express the antiderivative in terms of x:−3x2−1+C
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