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Multiple Choice
Given the parametric equations , for , what is the area enclosed by the curve and the y-axis?
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Verified step by step guidance
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Step 1: Recall that the area enclosed by a parametric curve and the y-axis can be calculated using the formula: \( A = \int y \frac{dx}{dt} dt \), where \( y \) and \( x \) are given as parametric equations.
Step 2: Differentiate \( x = \sin^2(t) \) with respect to \( t \) to find \( \frac{dx}{dt} \). Using the chain rule, \( \frac{dx}{dt} = 2\sin(t)\cos(t) \).
Step 3: Substitute \( y = 2\cos(t) \) and \( \frac{dx}{dt} = 2\sin(t)\cos(t) \) into the area formula: \( A = \int_{0}^{\pi} 2\cos(t) \cdot 2\sin(t)\cos(t) dt \).
Step 4: Simplify the integrand. \( 2\cos(t) \cdot 2\sin(t)\cos(t) = 4\sin(t)\cos^2(t) \). The integral becomes \( A = \int_{0}^{\pi} 4\sin(t)\cos^2(t) dt \).
Step 5: Use a trigonometric identity to simplify \( \cos^2(t) \). Recall \( \cos^2(t) = \frac{1 + \cos(2t)}{2} \). Substitute this into the integral and proceed to evaluate \( A = \int_{0}^{\pi} 4\sin(t)\left(\frac{1 + \cos(2t)}{2}\right) dt \). Break the integral into simpler parts and solve each term.