Surface area of revolution for an ellipse

[erjkism]

Homework Statement

Find the surface area obtained when the upper half of the ellipse: $$\frac{x^{2}}{4}+ y^{2}=1$$ is rotated about the x-axis

Homework Equations

$$\int2piyds$$

The Attempt at a Solution

 

[Dick]

Please continue. ds=sqrt(1+(dy/dx)^2)*dy, correct?