What are the direction cosines of a plane and of a curve?

[DrDolittle]

dc's

what are the direction cosines of a plane and that of a curve.

Regards
drdolittle

 

[cedance]

Re: dc's

reg. the plane, i think its directly interpreted by defnition as,

suppose the equation is u = ai +bj+ck then,

cos α = a/ |u|, cos β = b/|u|, cos τ = c/|u|

0<=α,β,τ<=pi

that is, u is unit vector if a,b,c are the direction cosines of u.

i think the similar thing holds good for the circle also.. btw, i think it must be direction cosines to a plane and not direction cosines of a plane.. that makes the geometrical interpretation definition of DC different...

/Am

 

[dazhen]

dc's

Check out the definition of Direction Cosine from Erik's Mathworld.

https://mathworld.wolfram.com/DirectionCosine.html