Can you give step-by-step and how it being w.r.t to y-axis affect it?
The surface area equals
∫ 2πx ds, since the region is being rotated about the y-axis
= ∫ 2πx √(1 + (dy/dx)^2) dx
= ∫(x = 0 to 2) 2πx √(1 + (-2x)^2) dx, since y = 3 - x^2
= ∫(x = 0 to 2) 2πx (1 + 4x^2)^(1/2) dx
= ∫(u = 1 to 17) 2π u^(1/2) du/8, letting u = 1 + 4x^2, du = 8x dx
= (π/4) * (2/3)u^(3/2) {for u = 1 to 17}
= (π/6) (17^(3/2) - 1).
I hope this helps!
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Verified answer
The surface area equals
∫ 2πx ds, since the region is being rotated about the y-axis
= ∫ 2πx √(1 + (dy/dx)^2) dx
= ∫(x = 0 to 2) 2πx √(1 + (-2x)^2) dx, since y = 3 - x^2
= ∫(x = 0 to 2) 2πx (1 + 4x^2)^(1/2) dx
= ∫(u = 1 to 17) 2π u^(1/2) du/8, letting u = 1 + 4x^2, du = 8x dx
= (π/4) * (2/3)u^(3/2) {for u = 1 to 17}
= (π/6) (17^(3/2) - 1).
I hope this helps!