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Geometric Transformations Applied Linear Algebra MATH 5112/6012 Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 1/8

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Page 1: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Geometric Transformations

Applied Linear AlgebraMATH 5112/6012

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 1 / 8

Page 2: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Geometric Transformations

These are transformations R2 → R2 that include

translations

dilations

rotations

reflections

projections

shearing

By using compositions of these, we can create all sorts of transformations.

Many of the above can also be defined as maps Rn → Rn.

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 2 / 8

Page 3: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Geometric Transformations

These are transformations R2 → R2 that include

translations

dilations

rotations

reflections

projections

shearing

By using compositions of these, we can create all sorts of transformations.

Many of the above can also be defined as maps Rn → Rn.

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 2 / 8

Page 4: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Geometric Transformations

These are transformations R2 → R2 that include

translations

dilations

rotations

reflections

projections

shearing

By using compositions of these, we can create all sorts of transformations.

Many of the above can also be defined as maps Rn → Rn.

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 2 / 8

Page 5: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Geometric Transformations

These are transformations R2 → R2 that include

translations

dilations

rotations

reflections

projections

shearing

By using compositions of these, we can create all sorts of transformations.

Many of the above can also be defined as maps Rn → Rn.

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 2 / 8

Page 6: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Geometric Transformations

These are transformations R2 → R2 that include

translations

dilations

rotations

reflections

projections

shearing

By using compositions of these, we can create all sorts of transformations.

Many of the above can also be defined as maps Rn → Rn.

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 2 / 8

Page 7: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Geometric Transformations

These are transformations R2 → R2 that include

translations

dilations

rotations

reflections

projections

shearing

By using compositions of these, we can create all sorts of transformations.

Many of the above can also be defined as maps Rn → Rn.

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 2 / 8

Page 8: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Geometric Transformations

These are transformations R2 → R2 that include

translations

dilations

rotations

reflections

projections

shearing

By using compositions of these, we can create all sorts of transformations.

Many of the above can also be defined as maps Rn → Rn.

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 2 / 8

Page 9: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Geometric Transformations

These are transformations R2 → R2 that include

translations

dilations

rotations

reflections

projections

shearing

By using compositions of these, we can create all sorts of transformations.

Many of the above can also be defined as maps Rn → Rn.

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 2 / 8

Page 10: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Geometric Transformations

These are transformations R2 → R2 that include

translations

dilations

rotations

reflections

projections

shearing

By using compositions of these, we can create all sorts of transformations.

Many of the above can also be defined as maps Rn → Rn.

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 2 / 8

Page 11: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Translations and Dilations in R2

A translation of R2 by ~a is the map R2 T−→ R2 defined by

T (~x) = ~x + ~a ;

here ~a is some fixed vector in R2.

A dilation/scaling of R2 by k is the map R2 S−→ R2 defined by

S(~x) = k~x ;

here k > 0 is some fixed positive scalar.

Both translations and dilations can be defined in Rn; we can even useexactly the same formulas.

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 3 / 8

Page 12: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Translations and Dilations in R2

A translation of R2 by ~a is the map R2 T−→ R2 defined by

T (~x) = ~x + ~a ;

here ~a is some fixed vector in R2.

A dilation/scaling of R2 by k is the map R2 S−→ R2 defined by

S(~x) = k~x ;

here k > 0 is some fixed positive scalar.

Both translations and dilations can be defined in Rn; we can even useexactly the same formulas.

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 3 / 8

Page 13: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Translations and Dilations in R2

A translation of R2 by ~a is the map R2 T−→ R2 defined by

T (~x) = ~x + ~a ;

here ~a is some fixed vector in R2.

A dilation/scaling of R2 by k is the map R2 S−→ R2 defined by

S(~x) = k~x ;

here k > 0 is some fixed positive scalar.

Both translations and dilations can be defined in Rn; we can even useexactly the same formulas.

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 3 / 8

Page 14: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Translations and Dilations in R2

A translation of R2 by ~a is the map R2 T−→ R2 defined by

T (~x) = ~x + ~a ;

here ~a is some fixed vector in R2.

A dilation/scaling of R2 by k is the map R2 S−→ R2 defined by

S(~x) = k~x ;

here k > 0 is some fixed positive scalar.

Both translations and dilations can be defined in Rn; we can even useexactly the same formulas.

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 3 / 8

Page 15: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Translations and Dilations in R2

A translation of R2 by ~a is the map R2 T−→ R2 defined by

T (~x) = ~x + ~a ;

here ~a is some fixed vector in R2.

A dilation/scaling of R2 by k is the map R2 S−→ R2 defined by

S(~x) = k~x ;

here k > 0 is some fixed positive scalar.

Both translations and dilations can be defined in Rn; we can even useexactly the same formulas.

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 3 / 8

Page 16: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Rotations in R2

A rotation of R2 by θ is the map R2 R−→ R2 defined by letting R(~x) be thevector obtained by rotating ~x (about ~0) by θ radians (in the clockwisedirection).

~x

θ

R(~x)

Figure: Rotating R2 by θ radiansApplied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 4 / 8

Page 17: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Rotations in R2

A rotation of R2 by θ is the map R2 R−→ R2 defined by letting R(~x) be thevector obtained by rotating ~x (about ~0) by θ radians (in the clockwisedirection).

~x

θ

R(~x)

Figure: Rotating R2 by θ radiansApplied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 4 / 8

Page 18: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Rotations in R2

A rotation of R2 by θ is the map R2 R−→ R2 defined by letting R(~x) be thevector obtained by rotating ~x (about ~0) by θ radians (in the clockwisedirection).

~x

θ

R(~x)

Figure: Rotating R2 by θ radiansApplied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 4 / 8

Page 19: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Rotations in R2

A rotation of R2 by θ is the map R2 R−→ R2 defined by letting R(~x) be thevector obtained by rotating ~x (about ~0) by θ radians (in the clockwisedirection).

~x

θ

R(~x)

Figure: Rotating R2 by θ radiansApplied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 4 / 8

Page 20: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Rotations in R2

A rotation of R2 by θ is the map R2 R−→ R2 defined by letting R(~x) be thevector obtained by rotating ~x (about ~0) by θ radians (in the clockwisedirection).

~x

θ

R(~x)

Figure: Rotating R2 by θ radiansApplied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 4 / 8

Page 21: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Rotations in R2

A rotation of R2 by θ is the map R2 R−→ R2 defined by letting R(~x) be thevector obtained by rotating ~x (about ~0) by θ radians (in the clockwisedirection).

~x

θ

R(~x)

Figure: Rotating R2 by θ radiansApplied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 4 / 8

Page 22: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Reflections in R2

The reflection R2 R−→ R2 across L is given by letting R(~x) be the vectorobtained by reflecting ~x across the line L;

L is some fixed line in R2.

x

y [xy

]

[x−y

]

[−xy

]

Reflection across the x-axis is

R([xy

])=

[x−y

].

Reflection across the y -axis is

R([xy

])=

[−xy

].

Reflection across the line y = x is

R([xy

])=

[yx

].

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 5 / 8

Page 23: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Reflections in R2

The reflection R2 R−→ R2 across L is given by letting R(~x) be the vectorobtained by reflecting ~x across the line L; L is some fixed line in R2.

x

y [xy

]

[x−y

]

[−xy

]

Reflection across the x-axis is

R([xy

])=

[x−y

].

Reflection across the y -axis is

R([xy

])=

[−xy

].

Reflection across the line y = x is

R([xy

])=

[yx

].

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 5 / 8

Page 24: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Reflections in R2

The reflection R2 R−→ R2 across L is given by letting R(~x) be the vectorobtained by reflecting ~x across the line L; L is some fixed line in R2.

x

y [xy

]

[x−y

]

[−xy

]

Reflection across the x-axis is

R([xy

])=

[x−y

].

Reflection across the y -axis is

R([xy

])=

[−xy

].

Reflection across the line y = x is

R([xy

])=

[yx

].

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 5 / 8

Page 25: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Reflections in R2

The reflection R2 R−→ R2 across L is given by letting R(~x) be the vectorobtained by reflecting ~x across the line L; L is some fixed line in R2.

x

y [xy

]

[x−y

]

[−xy

]

Reflection across the x-axis is

R([xy

])=

[x−y

].

Reflection across the y -axis is

R([xy

])=

[−xy

].

Reflection across the line y = x is

R([xy

])=

[yx

].

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 5 / 8

Page 26: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Reflections in R2

The reflection R2 R−→ R2 across L is given by letting R(~x) be the vectorobtained by reflecting ~x across the line L; L is some fixed line in R2.

x

y [xy

]

[x−y

]

[−xy

]Reflection across the x-axis is

R([xy

])=

[x−y

].

Reflection across the y -axis is

R([xy

])=

[−xy

].

Reflection across the line y = x is

R([xy

])=

[yx

].

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 5 / 8

Page 27: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Reflections in R2

The reflection R2 R−→ R2 across L is given by letting R(~x) be the vectorobtained by reflecting ~x across the line L; L is some fixed line in R2.

x

y [xy

]

[x−y

]

[−xy

]Reflection across the x-axis is

R([xy

])=

[x−y

].

Reflection across the y -axis is

R([xy

])=

[−xy

].

Reflection across the line y = x is

R([xy

])=

[yx

].

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 5 / 8

Page 28: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Projections in R2

The projection R2 P−→ R2 onto L is given by letting P(~x) be the vectorobtained by orthogonally projecting ~x onto the direction vector for the lineL;

L is some fixed line in R2.

x

y [xy

]

[x0

][

0y

]

We will discuss projections at greatlength in Chapter 6!

Projection onto the x-axis is

P([xy

])=

[x0

].

Projection onto the y -axis is

P([xy

])=

[0y

].

Projection onto the line y = x ,

P([xy

])=

x + y

2

[11

].

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 6 / 8

Page 29: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Projections in R2

The projection R2 P−→ R2 onto L is given by letting P(~x) be the vectorobtained by orthogonally projecting ~x onto the direction vector for the lineL; L is some fixed line in R2.

x

y [xy

]

[x0

][

0y

]

We will discuss projections at greatlength in Chapter 6!

Projection onto the x-axis is

P([xy

])=

[x0

].

Projection onto the y -axis is

P([xy

])=

[0y

].

Projection onto the line y = x ,

P([xy

])=

x + y

2

[11

].

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 6 / 8

Page 30: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Projections in R2

The projection R2 P−→ R2 onto L is given by letting P(~x) be the vectorobtained by orthogonally projecting ~x onto the direction vector for the lineL; L is some fixed line in R2.

x

y [xy

]

[x0

][

0y

]

We will discuss projections at greatlength in Chapter 6!

Projection onto the x-axis is

P([xy

])=

[x0

].

Projection onto the y -axis is

P([xy

])=

[0y

].

Projection onto the line y = x ,

P([xy

])=

x + y

2

[11

].

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 6 / 8

Page 31: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Projections in R2

The projection R2 P−→ R2 onto L is given by letting P(~x) be the vectorobtained by orthogonally projecting ~x onto the direction vector for the lineL; L is some fixed line in R2.

x

y [xy

][x0

]

[0y

]

We will discuss projections at greatlength in Chapter 6!

Projection onto the x-axis is

P([xy

])=

[x0

].

Projection onto the y -axis is

P([xy

])=

[0y

].

Projection onto the line y = x ,

P([xy

])=

x + y

2

[11

].

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 6 / 8

Page 32: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Projections in R2

The projection R2 P−→ R2 onto L is given by letting P(~x) be the vectorobtained by orthogonally projecting ~x onto the direction vector for the lineL; L is some fixed line in R2.

x

y [xy

][x0

][

0y

]

We will discuss projections at greatlength in Chapter 6!

Projection onto the x-axis is

P([xy

])=

[x0

].

Projection onto the y -axis is

P([xy

])=

[0y

].

Projection onto the line y = x ,

P([xy

])=

x + y

2

[11

].

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 6 / 8

Page 33: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Projections in R2

The projection R2 P−→ R2 onto L is given by letting P(~x) be the vectorobtained by orthogonally projecting ~x onto the direction vector for the lineL; L is some fixed line in R2.

x

y [xy

][x0

][

0y

]

We will discuss projections at greatlength in Chapter 6!

Projection onto the x-axis is

P([xy

])=

[x0

].

Projection onto the y -axis is

P([xy

])=

[0y

].

Projection onto the line y = x ,

P([xy

])=

x + y

2

[11

].

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 6 / 8

Page 34: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Orthogonal Projection Onto a Vector

Let ~u be a fixed vector, and ~x a variable vector.

~u

~x

~p

~zThe orthogonal projection of ~x onto ~uis the pictured vector ~p which is parallelto ~u (so, ~p = s~u for some scalar) andhas the property that ~z = ~x − ~p ⊥ ~u.

In Chapter 6 we will see that it is easyto determine s.

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 7 / 8

Page 35: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Orthogonal Projection Onto a Vector

Let ~u be a fixed vector, and ~x a variable vector.

~u

~x

~p

~zThe orthogonal projection of ~x onto ~uis the pictured vector ~p which is parallelto ~u (so, ~p = s~u for some scalar) andhas the property that ~z = ~x − ~p ⊥ ~u.

In Chapter 6 we will see that it is easyto determine s.

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 7 / 8

Page 36: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Orthogonal Projection Onto a Vector

Let ~u be a fixed vector, and ~x a variable vector.

~u

~x

~p

~zThe orthogonal projection of ~x onto ~uis the pictured vector ~p which is parallelto ~u (so, ~p = s~u for some scalar) andhas the property that ~z = ~x − ~p ⊥ ~u.

In Chapter 6 we will see that it is easyto determine s.

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 7 / 8

Page 37: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Orthogonal Projection Onto a Vector

Let ~u be a fixed vector, and ~x a variable vector.

~u

~x

~p

~zThe orthogonal projection of ~x onto ~uis the pictured vector ~p which is parallelto ~u (so, ~p = s~u for some scalar) andhas the property that ~z = ~x − ~p ⊥ ~u.

In Chapter 6 we will see that it is easyto determine s.

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 7 / 8

Page 38: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Orthogonal Projection Onto a Vector

Let ~u be a fixed vector, and ~x a variable vector.

~u

~x

~p

~zThe orthogonal projection of ~x onto ~uis the pictured vector ~p which is parallelto ~u (so, ~p = s~u for some scalar) andhas the property that ~z = ~x − ~p ⊥ ~u.

In Chapter 6 we will see that it is easyto determine s.

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 7 / 8

Page 39: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Orthogonal Projection Onto a Vector

Let ~u be a fixed vector, and ~x a variable vector.

~u

~x

~p

~zThe orthogonal projection of ~x onto ~uis the pictured vector ~p which is parallelto ~u (so, ~p = s~u for some scalar) andhas the property that ~z = ~x − ~p ⊥ ~u.

In Chapter 6 we will see that it is easyto determine s.

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 7 / 8

Page 40: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Orthogonal Projection Onto a Vector

Let ~u be a fixed vector, and ~x a variable vector.

~u

~x

~p

~z

The orthogonal projection of ~x onto ~uis the pictured vector ~p

which is parallelto ~u (so, ~p = s~u for some scalar) andhas the property that ~z = ~x − ~p ⊥ ~u.

In Chapter 6 we will see that it is easyto determine s.

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 7 / 8

Page 41: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Orthogonal Projection Onto a Vector

Let ~u be a fixed vector, and ~x a variable vector.

~u

~x

~p

~z

The orthogonal projection of ~x onto ~uis the pictured vector ~p which is parallelto ~u (so, ~p = s~u for some scalar) andhas the property that

~z = ~x − ~p ⊥ ~u.

In Chapter 6 we will see that it is easyto determine s.

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 7 / 8

Page 42: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Orthogonal Projection Onto a Vector

Let ~u be a fixed vector, and ~x a variable vector.

~u

~x

~p

~zThe orthogonal projection of ~x onto ~uis the pictured vector ~p which is parallelto ~u (so, ~p = s~u for some scalar) andhas the property that ~z = ~x − ~p ⊥ ~u.

In Chapter 6 we will see that it is easyto determine s.

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 7 / 8

Page 43: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections

Orthogonal Projection Onto a Vector

Let ~u be a fixed vector, and ~x a variable vector.

~u

~x

~p

~zThe orthogonal projection of ~x onto ~uis the pictured vector ~p which is parallelto ~u (so, ~p = s~u for some scalar) andhas the property that ~z = ~x − ~p ⊥ ~u.

In Chapter 6 we will see that it is easyto determine s.

Applied Linear Algebra Linear Tfms Chapter 3, Section 6, Geo Tfms 7 / 8

Page 44: Geometric Transformations - UC Homepagesherronda/linear_algebra/...Geometric Transformations These are transformations R2!R2 that include translations dilations rotations re ections