#derivation of the formula circled

21 messages · Page 1 of 1 (latest)

spiral geyser
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what is the derivation of the formula circled?

bronze pantherBOT
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river veldt
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Well

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$$d=p \cdot n$$

young starBOT
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PapaBread

river veldt
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And to project with dot product you need to divide by the norm of the vector youre trying to project onto

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$$proj_n p = \frac{p \cdot n}{\abs{n}}$$

young starBOT
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PapaBread

river veldt
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So if you just substitute d into this and expand norm(n) then you get your formula

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$$proj_n p = \frac{d}{\sqrt{n_1^2+n_2^2+n_3^2}}$$

young starBOT
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PapaBread

river veldt
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@spiral geyser

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Heres a visualization of what we're doing if it helps at all

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You can see how the projection onto n of p gives you the distance to the origin

spiral geyser
hearty sonnetBOT
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@spiral geyser has given 1 rep to @river veldt

river veldt
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If you need any more explanation just ask

spiral geyser