55 10 1 point Let y F VI E Compute the distance d from y to
5.5 10
(1 point) Let y F VI E Compute the distance d from y to the subspace of R4 spanned by Vi and v2. EESolution
we can write, y = p + (y-p); where p is projection of y in subspace R^4;
we need to find ||y-p||;
Now to find p in given subspace, we need to find normal and ortho-normal vectors in this subspace,
i.e. from v1 and v2 we need to calculate x1 and x2 which are normal and ortho normal vectors in same sub space,
here x1 = v1/|v1|
i.e. x1 = [2,-4,-2,1]/sqrt(25) = [2,-4,-2,1]/5;
and x2 = (v2 - <v2,x1>x1) / |(v2 - <v2,x1>x1)|
Where, where <v2,x1> = inner product of two vectors= (2*2 + (-2*-4)+(-2*4)+1*-4)/5
= 0;
x2 = [2,-2,4,-4]/6
x2 = [1,-1,2,-2]/3
so projection of y over subspace spanned by {x1,x2} is
p = <y,x1>x1 + <y,x2>x2;
where y = [-5,-1,0,1]
<y,x1> = (-5)/5 = -1;
<y,x2> = (-12)/6 = -2
p = [-2,4,2,1]/5+ [-4,4,-8,8]/3
p = [-26,32,-34,43]/15
the distance is d = |y-p|
d = sqrt (4705)/15
d = 4.572 is the answer.
