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@@ -52,19 +52,22 @@ $$
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- 2D：
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- 2D：
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-$
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+$$
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\vec{a} \cdot \vec{b} =
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\vec{a} \cdot \vec{b} =
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(^{x_a} _{y_a})
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(^{x_a} _{y_a})
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\cdot
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\cdot
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(^{x_b} _{y_b}) = x_a*x_b + y_a*y_b
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(^{x_b} _{y_b}) = x_a*x_b + y_a*y_b
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-$
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+$$
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- 3D：
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- 3D：
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-$\vec{a} \cdot \vec{b} =
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+
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+$$
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+\vec{a} \cdot \vec{b} =
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\begin{pmatrix} x_a \\ y_a \\ z_a\end{pmatrix}
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\begin{pmatrix} x_a \\ y_a \\ z_a\end{pmatrix}
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\cdot
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\cdot
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\begin{pmatrix} x_b \\ y_b \\ y_c \end{pmatrix}
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\begin{pmatrix} x_b \\ y_b \\ y_c \end{pmatrix}
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-= x_a * x_b + y_a * y_b + z_a * z_b $
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+= x_a * x_b + y_a * y_b + z_a * z_b
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+$$
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