- #1
Daren H
- 5
- 0
Homework Statement
Determine whether the following are linear transformations from R2 into R3:
Homework Equations
a) L(x)=(x1, x2, 1)^t
b) L(x)=(x1, x2, x1+2x2)^t
c) L(x)=(x1, 0, 0)^t
d) L(x)=(x1, x2, x1^2+x2^2)^t
The Attempt at a Solution
To show L is a linear transformation, I need to be able to show:
1. L(a*x1+b*x2)=aL(x1)+bL(x2);
2. L(x1+x2)=L(x1)+L(x2);
3. L(a*x1)=aL(x1);
By looking and playing around with this, I can see how d is not a transformation, since if I let a=-1 and b=-2, then rule 3 does not hold. If I'm wrong, please correct me.
But as far as a, b, and c, it looks like all three rules hold. The appendix says a is not a transformation, but I'm not sure why. It seems to me that a also satisfies the 3 conditions, what am I missing? Is there an easier way to do this? Can someone explain this to me like I'm two years old?
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