Q. Evaluate the integral and express your answer in simplest form.∫xx2−19dxAnswer:
Recognize standard inverse trigonometric form: Recognize the integral as a standard inverse trigonometric form. The integral resembles the form of the derivative of inverse hyperbolic functions, specifically the inverse hyperbolic secant. The standard form is ∫xx2−11dx=arcsech(x)+C, where C is the constant of integration.
Factor out constant: Factor out the constant from the integral. The integral can be rewritten by factoring out the constant 9: I=∫xx2−19dx=9×∫xx2−11dx
Apply standard form: Apply the standard form of the inverse hyperbolic secant.Using the standard form, we can write the integral as:I=9×arcsech(x)+CHowever, we need to express the answer in terms of the natural logarithm, as the arcsech function is not commonly used in simplest form.
Express in natural logarithm: Express arcsech(x) in terms of natural logarithm.The inverse hyperbolic secant can be expressed as:arcsech(x)=ln(x1+x21−1)
Substitute into integral: Substitute the expression for arcsech(x) into the integral.I=9⋅ln(x1+x21−1)+C
Simplify inside logarithm: Simplify the expression inside the logarithm.Since we have x1 inside the logarithm, we can simplify the expression by multiplying the numerator and denominator by x:I=9⋅ln(x1+x2−1)+C
Check for errors: Check for any possible simplifications or errors.The expression inside the logarithm is already in its simplest form, and there are no apparent math errors.
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