5: In order to intersect itself at two different times t and s, the equality x(t) = x(s) would have to be true, which yields s = −t. But then y(s) = −y(t) ≠ y(t). The y-coordinates cannot agree as they are never zero, so the opposite sign means that they are different. Thus no intersection is possible.

Thus the length is

Simplify the polynomial under the root.

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