Math

QuestionSimplify 4x2\sqrt{4-x^{2}} using the substitution x=2sinθx=2 \sin \theta.

Studdy Solution

STEP 1

Assumptions1. The given expression is 4x\sqrt{4-x^{}} . The substitution to be made is x=sinθx= \sin \theta
3. θ\theta is a real number

STEP 2

Substitute x=2sinθx=2 \sin \theta into the expression.
4(2sinθ)2\sqrt{4-(2 \sin \theta)^{2}}

STEP 3

implify the expression inside the square root.
sin2θ\sqrt{- \sin^{2} \theta}

STEP 4

Factor out the common factor of4 from the expression inside the square root.
4(1sin2θ)\sqrt{4(1-\sin^{2} \theta)}

STEP 5

Use the Pythagorean identity 1sin2θ=cos2θ1-\sin^{2}\theta=\cos^{2}\theta to simplify the expression inside the square root.
4cos2θ\sqrt{4\cos^{2} \theta}

STEP 6

Take the square root of the expression inside the square root.
2cosθ2|\cos \theta|

STEP 7

Since θ\theta is a real number, the absolute value can be removed, leaving the final simplified expression.
2cosθ2\cos \thetaThe simplified expression is 2cosθ2\cos \theta.

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