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Ind the area of the surface generated by revolving the curve about the indicated axis: y = x, 2/3 ≤ x ≤ 2/9; x-axis.

A. (2/7)π

B. (6/7)π

C. (2/7 - 6/3)π

D. (6/19 - 6/7)π

User Dooburt
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Final answer:

To find the area of the surface generated by revolving the curve y = x between x = 2/3 and x = 2/9 around the x-axis, integrate the function multiplied by 2π over the given interval. The calculated area is 64π/81, which doesn't match any of the given answer choices, indicating a possible error in the question or choices.

Step-by-step explanation:

The question asks us to find the area of the surface generated by revolving the curve y = x around the x-axis, between the limits x = 2/3 and x = 2/9. To do this, we use the formula for the surface area of a revolved curve around the x-axis S = 2π∫_a^b y ∙ √dx, where y is the function in terms of x, and [a, b] are the limits of integration.

Substituting the given function into the formula gives us:

S = 2π∫_(2/9)^(2/3) x ∙ √dx

We can calculate this definite integral by first finding the antiderivative of x, which is ½x², and then evaluate it at the upper and lower limits of integration and multiplying by 2π.

So the integral from 2/9 to 2/3 of x dx equals ½[(2/3)² - (2/9)²], and this leads to:S = 2π[½(4/9 - 4/81)] = 2π(36/81 - 4/81) = 2π(32/81) = 64π/81

The values provided in the question as answer choices do not match the correct calculation. Therefore, it's possible there might have been an error either in the question or in the answer choices provided. It should be ensured that the question and the answer choices correspond correctly.

User Pardeep Poria
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