# vector sketching

• Sep 28th 2010, 06:14 PM
jean91890
vector sketching
i am trying to figure these out but my answer are marked wrong.
my teacher wont explain it to me.

according to my textbook the projvu= [ (u dot v)/(v dot v) ] times v

consider the vectors u and v shown below
Attachment 19102

a) sketch projuv
this would be the projection of v onto u

my answer was the red vector below
Attachment 19103

b) sketch u-projvu
i put this as the answer and the teacher said that it wasn't completely wrong but there's something missing
Attachment 19104

c) determine the exact value of (u-projvu) dotted with v. show work.
i have no idea what to do here. i know that the projection of u onto v = [ (u dot v)/(v dot v) ] times v
but i dont know what to do after thathttp://www.mathhelpforum.com/math-he...isc/pencil.png
• Oct 23rd 2010, 06:55 PM
TKHunny
Quote:

Originally Posted by jean91890
[ (u dot v)/(v dot v) ] times v

It may make a little more sense if you write it like this: $(u\circ v)\cdot\frac{v}{(v\circ v)}$

Perhaps this: $(u\circ v)\cdot\frac{v}{||v||}}$