Let position vector .

The position vector and its tangential vector are perpendicular to each other, then .

Consider .

Differentiation formula: .

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.

Vector formula: .

.

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Magnitude of a vector is .

If the position vector and its tangential vector are perpendicular to each other then the curve lies on the sphere.

If the position vector and its tangential vector are perpendicular to each other then the curve lies on the sphere.