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1d
comment How to find the slope of a line when you only have a point and an angle?
Remember $\text{slope} = \tan \psi$ where $\psi$ is the angle from the x-axis and counter clockwise.
1d
comment Please help me find a formula to find the 3rd point in a right triangle
$$\tan(30°) = \frac{1}{\sqrt{3}}$$ Also for a vector $(x,y)$ the perpendicular is $(-y,x)$ so point C is on the line perpendicular to AB and passing through A.
2d
comment Abbreviated notation for “vector normalized by its length” (unit vector)
Great, but if you do use vector notation then $$\hat{\vec{x}}$$ is rather ugly. I have seen $$\langle \vec{x} \rangle$$ sometimes though.
2d
revised How to understand rotation around a point VS rotation of axes?
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Apr
24
comment calculate arbitrary points from a plane equation
From the information I in this answer use the two direction vectors to form a rectangle.
Apr
24
revised calculate arbitrary points from a plane equation
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Apr
24
revised calculate arbitrary points from a plane equation
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Apr
24
revised calculate arbitrary points from a plane equation
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Apr
24
revised calculate arbitrary points from a plane equation
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Apr
23
comment Volume from equation $(x ^2+ y ^2 + z ^2 ) ^2 = xyz$
Yes, I fixed it. In spherical coordinates the distance is implicitly considered always positive and thus the absolute value in the expression for $r$.
Apr
23
revised Volume from equation $(x ^2+ y ^2 + z ^2 ) ^2 = xyz$
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Apr
23
comment calculate arbitrary points from a plane equation
Possible duplicate of How do I get three non-colinear points on a plane?
Apr
23
comment calculate arbitrary points from a plane equation
Possible related question/answer on SO (stackoverflow.com/a/23474396/380384)
Apr
23
answered calculate arbitrary points from a plane equation
Apr
23
answered Volume from equation $(x ^2+ y ^2 + z ^2 ) ^2 = xyz$
Apr
17
comment Tangent parallel to the initial line for polar equation =, can r^2 be used instead?
You mean minimum right? And only with the form $y=\sqrt{1+x^2}$ the minimum is the same as $y^2=1+x^2$.
Apr
17
revised Tangent parallel to the initial line for polar equation =, can r^2 be used instead?
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Apr
17
answered Vector representation
Apr
16
comment Use least squares to find best fit value of angle phi
$s$ is a scale in order to make the $M$ matrix orthonormal ($M^\top M = \mathtt{1}$) and thus like a rotation matrix. By pulling the skew symmetric part out of $A$ we have almost a rotation, except for the scaling factor $1+s$. Again we want to minimize $s$, or at least be happy it is small value.
Apr
14
revised What is the value of $\tan (\frac{\pi}{2} - \epsilon)$?
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