Q. Evaluate the integral and express your answer in simplest form.∫4−x26dxAnswer:
Recognize standard form: Recognize the integral as a standard form. The integral ∫4−x26dx resembles the integral of the form ∫a2−u2du, which is a standard inverse trigonometric integral.
Trigonometric substitution: Use a trigonometric substitution. Let x=2sin(θ), which implies dx=2cos(θ)dθ. The limits of integration will change accordingly if this were a definite integral, but since it's an indefinite integral, we will substitute back to x at the end.
Substitute x with 2sin(θ): Substitute x with 2sin(θ) in the integral.The integral becomes ∫4−(2sin(θ))26⋅2cos(θ)dθ.
Simplify the integral: Simplify the integral.The integral simplifies to \int\frac{\(6\)}{\sqrt{\(4\)\(-4\)\sin^\(2\)(\theta)}} \cdot \(2\cos(\theta)d\theta = \int\frac{6}{\sqrt{4(1-\sin^2(\theta))}} \cdot 2\cos(\theta)d\theta\.
Use Pythagorean identity: Use the Pythagorean identity sin2(θ)+cos2(θ)=1. The integral further simplifies to ∫2cos2(θ)6⋅2cos(θ)dθ=∫cos(θ)6⋅2cos(θ)dθ.
Cancel cos(θ) terms: Cancel out the cos(θ) terms.The integral simplifies to ∫6×2dθ=∫12dθ.
Integrate with respect to θ: Integrate with respect to θ. The integral of 12 with respect to θ is 12θ.
Substitute back to x: Substitute back to x using the original substitution x=2sin(θ).We need to solve for θ in terms of x. Since x=2sin(θ), we have sin(θ)=2x. Therefore, θ=arcsin(2x).
Write final answer: Write the final answer.The final answer is 12θ+C, where C is the constant of integration. Substituting θ back, we get 12arcsin(x/2)+C.
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