Euclidean angle - Revision history

Eric Lengyel at 01:31, 8 July 2024

2024-07-08T01:31:19Z

Eric Lengyel at 21:28, 21 April 2024

2024-04-21T21:28:15Z

← Older revision		Revision as of 21:28, 21 April 2024
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	$$\cos \phi(\mathbf g, \mathbf h) = (\mathbf g_{xyz} \cdot \mathbf h_{xyz}) \mathbf 1 + \left\Vert\mathbf g \right\Vert_\unicode{x25CB}\left\Vert\mathbf h \right\Vert_\unicode{x25CB}$$		$$\cos \phi(\mathbf g, \mathbf h) = (\mathbf g_{xyz} \cdot \mathbf h_{xyz}) \mathbf 1 + \left\Vert\mathbf g \right\Vert_\unicode{x25CB}\left\Vert\mathbf h \right\Vert_\unicode{x25CB}$$
	\| style="padding: 12px; text-align: center;" \| [[Image:angle_plane_plane.svg\|~~122px~~]]		\| style="padding: 12px; text-align: center;" \| [[Image:angle_plane_plane.svg\|200px]]
	\|-		\|-
	\| style="padding: 12px;" \| Cosine of angle $$\phi$$ between plane $$\mathbf g$$ and line $$\boldsymbol l$$.		\| style="padding: 12px;" \| Cosine of angle $$\phi$$ between plane $$\mathbf g$$ and line $$\boldsymbol l$$.

	$$\cos \phi(\mathbf g, \boldsymbol l) = \left\Vert \mathbf g_{xyz} \times \boldsymbol l_{\mathbf v}\right\Vert \mathbf 1 + \left\Vert\mathbf g \right\Vert_\unicode{x25CB}\left\Vert\boldsymbol l \right\Vert_\unicode{x25CB}$$		$$\cos \phi(\mathbf g, \boldsymbol l) = \left\Vert \mathbf g_{xyz} \times \boldsymbol l_{\mathbf v}\right\Vert \mathbf 1 + \left\Vert\mathbf g \right\Vert_\unicode{x25CB}\left\Vert\boldsymbol l \right\Vert_\unicode{x25CB}$$
	\| style="padding: 12px; text-align: center;" \| [[Image:angle_plane_line.svg\|~~250px~~]]		\| style="padding: 12px; text-align: center;" \| [[Image:angle_plane_line.svg\|200px]]
	\|-		\|-
	\| style="padding: 12px;" \| Cosine of angle $$\phi$$ between lines $$\boldsymbol l$$ and line $$\mathbf k$$.		\| style="padding: 12px;" \| Cosine of angle $$\phi$$ between lines $$\boldsymbol l$$ and line $$\mathbf k$$.

	$$\cos \phi(\boldsymbol l, \mathbf k) = (\boldsymbol l_{\mathbf v} \cdot \mathbf k_{\mathbf v})\mathbf 1 + \left\Vert\boldsymbol l \right\Vert_\unicode{x25CB}\left\Vert\mathbf k \right\Vert_\unicode{x25CB}$$		$$\cos \phi(\boldsymbol l, \mathbf k) = (\boldsymbol l_{\mathbf v} \cdot \mathbf k_{\mathbf v})\mathbf 1 + \left\Vert\boldsymbol l \right\Vert_\unicode{x25CB}\left\Vert\mathbf k \right\Vert_\unicode{x25CB}$$
	\| style="padding: 12px; text-align: center;" \| [[Image:angle_line_line.svg\|~~250px~~]]		\| style="padding: 12px; text-align: center;" \| [[Image:angle_line_line.svg\|200px]]
	\|}		\|}

Eric Lengyel: Created page with "The cosine of the Euclidean angle $$\cos \phi(\mathbf a, \mathbf b)$$ between two geometric objects '''a''' and '''b''' can be measured by the homogeneous magnitude given by :$$\cos \phi(\mathbf a, \mathbf b) = \left\Vert \mathbf a \vee \mathbf b^\unicode["segoe ui symbol"]{x2606}\right\Vert_\unicode{x25CF} + \left\Vert\mathbf a \right\Vert_\unicode{x25CB}\left\Vert\mathbf b \right\Vert_\unicode{x25CB}$$. In the case that the grades of $$\mathbf a$$ and $$\mathbf b..."

2024-04-21T21:27:37Z

Created page with "The cosine of the Euclidean angle $$\cos \phi(\mathbf a, \mathbf b)$$ between two geometric objects '''a''' and '''b''' can be measured by the homogeneous magnitude given by :$$\cos \phi(\mathbf a, \mathbf b) = \left\Vert \mathbf a \vee \mathbf b^\unicode["segoe ui symbol"]{x2606}\right\Vert_\unicode{x25CF} + \left\Vert\mathbf a \right\Vert_\unicode{x25CB}\left\Vert\mathbf b \right\Vert_\unicode{x25CB}$$. In the case that the grades of $$\mathbf a$$ and $$\mathbf b..."

New page

The cosine of the Euclidean angle $$\cos \phi(\mathbf a, \mathbf b)$$ between two geometric objects '''a''' and '''b''' can be measured by the homogeneous [[magnitude]] given by

:$$\cos \phi(\mathbf a, \mathbf b) = \left\Vert \mathbf a \vee \mathbf b^\unicode["segoe ui symbol"]{x2606}\right\Vert_\unicode{x25CF} + \left\Vert\mathbf a \right\Vert_\unicode{x25CB}\left\Vert\mathbf b \right\Vert_\unicode{x25CB}$$.

In the case that the grades of $$\mathbf a$$ and $$\mathbf b$$ are equal, a signed angle can be obtained by using the formula

:$$\cos \phi(\mathbf a, \mathbf b) = \mathbf a \vee \mathbf b^\unicode["segoe ui symbol"]{x2606} + \left\Vert\mathbf a \right\Vert_\unicode{x25CB}\left\Vert\mathbf b \right\Vert_\unicode{x25CB}$$.

The following table lists formulas for angles between the main types of geometric objects in the 4D rigid geometric algebra over 3D Euclidean space. These formulas are general and do not require the geometric objects to be [[unitized]]. Most of them become simpler if unitization can be assumed.

The [[lines]] and [[planes]] appearing in the distance formulas are defined as follows:

:$$\mathbf k = k_{vx} \mathbf e_{41} + k_{vy} \mathbf e_{42} + k_{vz} \mathbf e_{43} + k_{mx} \mathbf e_{23} + k_{my} \mathbf e_{31} + k_{mz} \mathbf e_{12}$$
:$$\boldsymbol l = l_{vx} \mathbf e_{41} + l_{vy} \mathbf e_{42} + l_{vz} \mathbf e_{43} + l_{mx} \mathbf e_{23} + l_{my} \mathbf e_{31} + l_{mz} \mathbf e_{12}$$
:$$\mathbf g = g_x \mathbf e_{423} + g_y \mathbf e_{431} + g_z \mathbf e_{412} + g_w \mathbf e_{321}$$
:$$\mathbf h = h_x \mathbf e_{423} + h_y \mathbf e_{431} + h_z \mathbf e_{412} + h_w \mathbf e_{321}$$

{| class="wikitable"
! Angle Formula !! Illustration
|-
| style="padding: 12px;" | Cosine of angle $$\phi$$ between planes $$\mathbf g$$ and $$\mathbf h$$.

$$\cos \phi(\mathbf g, \mathbf h) = (\mathbf g_{xyz} \cdot \mathbf h_{xyz}) \mathbf 1 + \left\Vert\mathbf g \right\Vert_\unicode{x25CB}\left\Vert\mathbf h \right\Vert_\unicode{x25CB}$$
| style="padding: 12px; text-align: center;" | [[Image:angle_plane_plane.svg|122px]]
|-
| style="padding: 12px;" | Cosine of angle $$\phi$$ between plane $$\mathbf g$$ and line $$\boldsymbol l$$.

$$\cos \phi(\mathbf g, \boldsymbol l) = \left\Vert \mathbf g_{xyz} \times \boldsymbol l_{\mathbf v}\right\Vert \mathbf 1 + \left\Vert\mathbf g \right\Vert_\unicode{x25CB}\left\Vert\boldsymbol l \right\Vert_\unicode{x25CB}$$
| style="padding: 12px; text-align: center;" | [[Image:angle_plane_line.svg|250px]]
|-
| style="padding: 12px;" | Cosine of angle $$\phi$$ between lines $$\boldsymbol l$$ and line $$\mathbf k$$.

$$\cos \phi(\boldsymbol l, \mathbf k) = (\boldsymbol l_{\mathbf v} \cdot \mathbf k_{\mathbf v})\mathbf 1 + \left\Vert\boldsymbol l \right\Vert_\unicode{x25CB}\left\Vert\mathbf k \right\Vert_\unicode{x25CB}$$
| style="padding: 12px; text-align: center;" | [[Image:angle_line_line.svg|250px]]
|}

== In the Book ==

* Euclidean angles are discussed in Section 2.13.3.

== See Also ==

* [[Euclidean distance]]
* [[Geometric norm]]
* [[Magnitude]]
* [[Interior products]]

← Older revision		Revision as of 01:31, 8 July 2024
Line 1:		Line 1:
	The cosine of the Euclidean angle $$\cos \phi(\mathbf a, \mathbf b)$$ between two geometric objects '''a''' and '''b''' can be measured by the homogeneous [[magnitude]] given by		The cosine of the Euclidean angle $$\cos \phi(\mathbf a, \mathbf b)$$ between two geometric objects '''a''' and '''b''' can be measured by the homogeneous [[magnitude]] given by

	:$$\cos \phi(\mathbf a, \mathbf b) = \left\Vert \mathbf a \vee \mathbf b^\unicode["segoe ui symbol"]{x2606}\right\Vert_\unicode{x25CF} + \left\Vert\mathbf a \right\Vert_\unicode{x25CB}\left\Vert\mathbf b \right\Vert_\unicode{x25CB}$$.		:$$\cos \phi(\mathbf a, \mathbf b) = \left\Vert \mathbf a \vee \mathbf b^\unicode["segoe ui symbol"]{x2606}\right\Vert_\unicode["segoe ui symbol"]{x25CF} + \left\Vert\mathbf a \right\Vert_\unicode["segoe ui symbol"]{x25CB}\left\Vert\mathbf b \right\Vert_\unicode["segoe ui symbol"]{x25CB}$$.

	In the case that the grades of $$\mathbf a$$ and $$\mathbf b$$ are equal, a signed angle can be obtained by using the formula		In the case that the grades of $$\mathbf a$$ and $$\mathbf b$$ are equal, a signed angle can be obtained by using the formula

	:$$\cos \phi(\mathbf a, \mathbf b) = \mathbf a \vee \mathbf b^\unicode["segoe ui symbol"]{x2606} + \left\Vert\mathbf a \right\Vert_\unicode{x25CB}\left\Vert\mathbf b \right\Vert_\unicode{x25CB}$$.		:$$\cos \phi(\mathbf a, \mathbf b) = \mathbf a \vee \mathbf b^\unicode["segoe ui symbol"]{x2606} + \left\Vert\mathbf a \right\Vert_\unicode["segoe ui symbol"]{x25CB}\left\Vert\mathbf b \right\Vert_\unicode["segoe ui symbol"]{x25CB}$$.

	The following table lists formulas for angles between the main types of geometric objects in the 4D rigid geometric algebra over 3D Euclidean space. These formulas are general and do not require the geometric objects to be [[unitized]]. Most of them become simpler if unitization can be assumed.		The following table lists formulas for angles between the main types of geometric objects in the 4D rigid geometric algebra over 3D Euclidean space. These formulas are general and do not require the geometric objects to be [[unitized]]. Most of them become simpler if unitization can be assumed.
Line 21:		Line 21:
	\| style="padding: 12px;" \| Cosine of angle $$\phi$$ between planes $$\mathbf g$$ and $$\mathbf h$$.		\| style="padding: 12px;" \| Cosine of angle $$\phi$$ between planes $$\mathbf g$$ and $$\mathbf h$$.

	$$\cos \phi(\mathbf g, \mathbf h) = (\mathbf g_{xyz} \cdot \mathbf h_{xyz}) \mathbf 1 + \left\Vert\mathbf g \right\Vert_\unicode{x25CB}\left\Vert\mathbf h \right\Vert_\unicode{x25CB}$$		$$\cos \phi(\mathbf g, \mathbf h) = (\mathbf g_{xyz} \cdot \mathbf h_{xyz}) \mathbf 1 + \left\Vert\mathbf g \right\Vert_\unicode["segoe ui symbol"]{x25CB}\left\Vert\mathbf h \right\Vert_\unicode["segoe ui symbol"]{x25CB}$$
	\| style="padding: 12px; text-align: center;" \| [[Image:angle_plane_plane.svg\|200px]]		\| style="padding: 12px; text-align: center;" \| [[Image:angle_plane_plane.svg\|200px]]
	\|-		\|-
	\| style="padding: 12px;" \| Cosine of angle $$\phi$$ between plane $$\mathbf g$$ and line $$\boldsymbol l$$.		\| style="padding: 12px;" \| Cosine of angle $$\phi$$ between plane $$\mathbf g$$ and line $$\boldsymbol l$$.

	$$\cos \phi(\mathbf g, \boldsymbol l) = \left\Vert \mathbf g_{xyz} \times \boldsymbol l_{\mathbf v}\right\Vert \mathbf 1 + \left\Vert\mathbf g \right\Vert_\unicode{x25CB}\left\Vert\boldsymbol l \right\Vert_\unicode{x25CB}$$		$$\cos \phi(\mathbf g, \boldsymbol l) = \left\Vert \mathbf g_{xyz} \times \boldsymbol l_{\mathbf v}\right\Vert \mathbf 1 + \left\Vert\mathbf g \right\Vert_\unicode["segoe ui symbol"]{x25CB}\left\Vert\boldsymbol l \right\Vert_\unicode["segoe ui symbol"]{x25CB}$$
	\| style="padding: 12px; text-align: center;" \| [[Image:angle_plane_line.svg\|200px]]		\| style="padding: 12px; text-align: center;" \| [[Image:angle_plane_line.svg\|200px]]
	\|-		\|-
	\| style="padding: 12px;" \| Cosine of angle $$\phi$$ between lines $$\boldsymbol l$$ and line $$\mathbf k$$.		\| style="padding: 12px;" \| Cosine of angle $$\phi$$ between lines $$\boldsymbol l$$ and line $$\mathbf k$$.

	$$\cos \phi(\boldsymbol l, \mathbf k) = (\boldsymbol l_{\mathbf v} \cdot \mathbf k_{\mathbf v})\mathbf 1 + \left\Vert\boldsymbol l \right\Vert_\unicode{x25CB}\left\Vert\mathbf k \right\Vert_\unicode{x25CB}$$		$$\cos \phi(\boldsymbol l, \mathbf k) = (\boldsymbol l_{\mathbf v} \cdot \mathbf k_{\mathbf v})\mathbf 1 + \left\Vert\boldsymbol l \right\Vert_\unicode["segoe ui symbol"]{x25CB}\left\Vert\mathbf k \right\Vert_\unicode["segoe ui symbol"]{x25CB}$$
	\| style="padding: 12px; text-align: center;" \| [[Image:angle_line_line.svg\|200px]]		\| style="padding: 12px; text-align: center;" \| [[Image:angle_line_line.svg\|200px]]
	\|}		\|}