In: Advanced Math
Suppose we are given the unit square S in the plane with corners (0, 0), (1, 0), (1, 1) and (0, 1). Let T : R 2 → R 2 be a linear transformation represented by the matrix A. If T is not onto, will the image of S under the map T be a parallelogram, a line segment, or a point? Be sure to justify your answer.
We know that the area of the unit square will be
If
is not onto then
is not
trivial meaning
(as it
must be non-invertible)
This means that whatever the shape of the image of the unit
square under is, it is a figure with
area
It is impossible it is a parallelogram, but it is possible it is either a line segment or a point (last two are both possible)
For example,
transforms the unit square to the unit line segment along the
X-axis
And
transforms the unit square to the diagonal of the unit square
(line segments)
On the other hand,
transforms the unit square to the origin (single point)
All the examples above had T as a non-onto transformation
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