- #1
TimmyJ1203
- 19
- 0
Homework Statement
Hello, here is the question:
"Rather than use the standard definitions of addition and scalar multiplication in R3, suppose these two operations are defined as follows. With these new definitions, is R3 a vector space? Justify your answers.
a) (x1, y1, z1) + (x2, y2, z2) = (0,0,0)
c(x, y, z) = (cx, cy, cz)
b) (x1, y1, z1) + (x2, y2, z2) = (x1 + x2 + 9, y1 + y2 + 9, z1 + z2 + 9)
c(x, y, z) = (cx, cy, cz)
c) (x1, y1, z1) + (x2, y2, z2) = (x1 + x2 + 6, y1 + y2 + 6, z1 + z2 + 6)
c(x, y, z) = (cx + 6c - 6, cy + 6c - 6, cz + 6c - 6)"
Homework Equations
Here are the axioms we are supposed to use:
Assume u, v, w are in set V; let c and d be scalars.
1. u + v is in V (Closure under addition)
2. u + v = v + u (Commutative property)
3. u + (v + w) = (u + v) + w (Associative property)
4. V has a zero vector 0 such that for every u in V, u + 0 = u. (Additive identity)
5. For every u in V, there is a vector in V denoted by -u such that u + (-u) = 0. (Additive inverse)
6. cu is in V (Closure under scalar multiplication)
7. c(u + v) = cu + cv (Distributive property)
8. (c + d)u = cu + du (Distributive property)
9. c(du) = (cd)u (Associative property)
10. 1(u) = u (Scalar identity)
The Attempt at a Solution
Disclaimer: I don't know how to check the properties mechanically, but a forum moderator insisted that I show work.[/B]
Our professor didn't get the opportunity to go over any examples with us, so I'm not even sure where to begin.
b)
Verification of property 1:
(x_1 + x_2 + 9, y_1 + y_2 + 9, z_1 + z_2 + 9); all components are real, so property 1 fits.
Verification of property 2:
Switching the order of the terms makes components equivalent.
Verification of property 3:
Associating terms makes components equivalent.
Verification of property 4:
(x_1, y_1, z_1) + (0, 0, 0) = (x_1 + 9?, y_1 + 9?, z_1 + 9?)
So it fails the additive identity? Not sure.
Verification of property 5:
(x_1, y_1, z_1) + (-x_1, -y_1, -z_1) = (x_1 - x_1 + 9?, y_1 - y_1 + 9?, z_1 - z_1 + 9)
So it also fails the additive inverse? Not sure.
Verification of property 6:
Looks like this checks out. Not sure how to show work.
Verification of property 7:
Looks like this checks out. Not sure how to show work.
Verification of property 8:
Looks like this checks out. Not sure how to show work.
Verification of property 9:
Looks like this checks out. Not sure how to show work.
Verification of property 10:
Looks like this checks out. Not sure how to show work.