Note: Both of these problems can be done in more than one way.
Some ways are easier than others. If you take advantage of theorems,
not just definitions, the problems will be easier.
Let {v1, v2,
v3} be a basis for a vector space V.
Let u1 = v1,
u2= v1+v2,
u3=
v1+v2+v3.
Prove that {u1, u2,
u3} is a basis for V.
In P3, let p1,
p2, p3, p4
be the functions defined by