Q. Evaluate the integral and express your answer in simplest form.∫xx2−1−7dxAnswer:
Identify Substitution: Let's start by identifying a substitution that can simplify the integral. We notice that the denominator has the expression x2−1, which suggests a trigonometric substitution. Specifically, we can use the substitution x=sec(θ), because then x2−1 would become sec2(θ)−1=tan(θ). Let's perform this substitution.
Find dx in terms of d(θ): First, we need to find dx in terms of d(θ). Since x=sec(θ), we take the derivative of both sides with respect to θ to get d(θ)dx=sec(θ)tan(θ). Therefore, dx=sec(θ)tan(θ)d(θ).
Perform Substitution: Now we substitute x=sec(θ) and dx=sec(θ)tan(θ)d(θ) into the integral. The integral becomes:∫sec(θ)tan(θ)−7⋅sec(θ)tan(θ)d(θ)This simplifies to:∫(−7)d(θ)
Integrate Constant: The integral of a constant is just the constant times the variable of integration. So we have: −7×θ+C, where C is the constant of integration.
Back-Substitute for x: Now we need to back-substitute to get our answer in terms of x. We originally set x=sec(θ), so we need to solve for θ. We can do this by taking the inverse secant of both sides: θ=arcsec(x).
Final Answer: Substituting θ back into our integral result, we get:−7×arcsec(x)+CThis is our final answer in terms of x.
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