Question

just making sure I understand it....
\[S=\int_{a}^{b} 2\pi y \sqrt{1+{(\frac{dy}{dx})}^2} dx\]
\[S=\int_{c}^{d} 2\pi y \sqrt{1+{(\frac{dx}{dy})}^2} dy\]
\[S=\int_{a}^{b} 2\pi x \sqrt{1+{(\frac{dy}{dx})}^2} dx\]
One is for revolution about the x axis...the other for revolution about the y- axis...and then we have one more equation....why?

Answer 1

what the devil is this?

Answer 2

Area of a Surface of Revolution

Answer 3

surface area ?

Answer 4

yes

Answer 5

let me make some drawing

Answer 6

@TuringTest