# Principal normal

From Encyclopedia of Mathematics

A normal to a curve passing through a point of and lying in the osculating plane to at . If is the parametric equation of the curve and the value corresponds to , then the equation of the principal normal in vector form is:

#### Comments

#### References

[a1] | D.J. Struik, "Lectures in classical differential calculus" , Dover, reprint (1988) pp. 13 |

[a2] | R.S. Millman, G.D. Parker, "Elements of differential geometry" , Prentice-Hall (1977) pp. 26 |

**How to Cite This Entry:**

Principal normal. E.V. Shikin (originator),

*Encyclopedia of Mathematics.*URL: http://www.encyclopediaofmath.org/index.php?title=Principal_normal&oldid=15541

This text originally appeared in Encyclopedia of Mathematics - ISBN 1402006098