# Orthogonality

• Oct 30th 2009, 08:36 PM
JohnLeee
Orthogonality
http://i36.tinypic.com/2s0bje2t.jpg

I was thinking about using the chain rule because
(Dh)_t = ((Dh)_a(t)) o (Da)_t where I believe ((Dh)_a(t))=(grad h)(a(t))
but couldn't really relate this to a dot product that would be 0.
Any help would be greatly appreciated. Thanks
• Oct 30th 2009, 08:48 PM
Enrique2
We have that $h\circ \alpha (t)=c$ for all $t\in U$. Thus $(h\circ\alpha)'$ is identically 0 in $U$. Just apply the chain rule.