vector sketching--so confused!

[jenn91890]

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 proj[sub:vmnpwpgt]v[/sub:vmnpwpgt]u= [ (u dot v)/(v dot v) ] times v

consider the vectors u and v shown (in the attached picture)

a) sketch proj[sub:vmnpwpgt]u[/sub:vmnpwpgt]v
this would be the projection of v onto u

my answer was the red vector in attachment a

b) sketch u-proj[sub:vmnpwpgt]v[/sub:vmnpwpgt]u
i put this as the answer (attachment b)
and the teacher said that it wasn't completely wrong but there's something missing


c) determine the exact value of (u-proj[sub:vmnpwpgt]v[/sub:vmnpwpgt]u) 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 that

 

[Deleted member 4993]

Re: vector sketching

consider the vectors u and v shown (in the attached picture)

a) sketch proj[sub:rux98how]u[/sub:rux98how]v

b) sketch u-proj[sub:rux98how]v[/sub:rux98how]u

c) determine the exact value of (u-proj[sub:rux98how]v[/sub:rux98how]u) dotted with v. show work.

According to your textbook - what is the definition of proj[sub:rux98how]u[/sub:rux98how]v

Please show us your work, indicating exactly where you are stuck - so that you may know where to begin to help you.

 

[jenn91890]

could you please help me figure out what i am doing wrong?