Span Definition and 205 Threads

show that a subset W of vector space V is a subspace of V iff span(W)=W Can anyone help guide me along in this proof?

I'm stuck on the following problem: Describe the span of the vectors u1 and u2 in R^3, where u1 = (1, 1, 1), u2 = (1, −1, 1) I know that the span is a(u1)+b(u2), which becomes (a+b,a-b,a+b), but I don't know where to go from here. TIA.

[FONT=Arial Black]undefined what mass does a neutron star hove and what is its life span? and any other information on the subject would not go un-apiretiated

Question about "Span" Given 3 vectors: v1=(1,1,2) v2=(1,0,1) v3=(2,1,3) To determine if they span R^3, I placed these 3 vectors in an augmented matrix. I found the determinant to be 0 which means that the 3 vectors do NOT span R^3. My question is, since v1,v2,v3 are linearly dependent...

i have come to the conclusion that the psychological present is not an instant. It is not a point in time. Our brains work in a certain way that let's us see more than one instant at a time. This can be proven. Take a pencil, and whip it back and forth. You will see multiple pencils. Why is...