Finding the length of an elliptical spiral

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Okay, i had a very strange thought, it was

"Is it possible to find the length of an elliptical spiral whose major and minor axes were decreasing?"

Like for example lets say that

$$ \frac{a}{b} = n $$

Then if the major axis's decrease can me shown as $\frac{a}{k^2+1}$ and the minor axis's decrease can be shown as $\frac{b}{k^2+n}$ then

$$ e = \sqrt{1-\frac{k^2+n}{k^2+1}} = \sqrt{\frac{1-n}{k^2+1}} $$

Therefore is i define the spiral length as

$$ S = a \sum_{k=0}^{\infty} \frac{E(\sqrt{\frac{1-n}{k^2+1}})}{k^2+1} $$

Where $E(\sqrt{\frac{1-n}{k^2+1}})$ is the complete elliptic integral of the 2nd kind. This is defined as

$$ \int_0^{\pi/2}\sqrt{1-\frac{\sin^2(\Theta)(1-n)}{k^2+1}}d\Theta $$

The series converges, But im unsure of how to come up with the values. I don't even know how to try.