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Apr
27
answered How can I translate this problem into Matrix/Linear Algebra notation?
Apr
26
comment How can I translate this problem into Matrix/Linear Algebra notation?
So the formula is R(i,j) = H(i,j)*D(i,j) to get the return if each stock on each day? The to get the totals you do SUM(R(i,j),i=1:s) and SUM(R(i,j),j,1=d)? Please confirm and show an example in the question in order to make it clear what you want.
Apr
26
revised How can I translate this problem into Matrix/Linear Algebra notation?
changed * to times symbol
Apr
20
answered Find the sum of the roots of a quadratic function given the vertex of its graph
Apr
16
comment Laplace's equation in Polar coordinate, an example?
The above is not an equation but an expression.
Apr
14
revised Non-existing Limit of $\sin x$
edited title
Apr
14
comment Non-existing Limit of $\sin x$
by $sinx$ did you mean $\sin(x)$?
Apr
13
comment Intersection of two circular arcs with same center
Without a description of how Azimuth is measured the question is not well defined.
Apr
12
revised Distance between two rectangulars
added 103 characters in body
Apr
12
comment Distance between two rectangulars
Getting the minimum distance between a point and a line is easy. Getting the minimum distance between a point and a line segment is much harder to do right. You have to account for the ends and see if the minimum point falls outside the segment, and on which side.
Apr
12
answered Distance between two rectangulars
Apr
12
revised Some proprieties of the matrix $A^\top A$
added 4 characters in body; edited title
Apr
12
comment Some proprieties of the matrix $A^\top A$
Use ^\top for transposes.
Apr
9
comment Calculating the length of the semi-major axis from the general equation of an ellipse
Note: Use math.stackexchange.com/a/785054/3301 to find the center.
Apr
9
comment Calculating the length of the semi-major axis from the general equation of an ellipse
Just as I decided to write this exact answer you beat me to it.
Apr
7
revised How do I prove that $\arccos(x) + \arccos(-x)=\pi$ when $x \in [-1,1]$?
roman formatting of sines and cosines
Apr
2
answered Normal Vector of plane for Rotation
Apr
2
revised Normal Vector of plane for Rotation
Removed unnecessary text and code formatted expressions
Apr
1
answered Matrix multiplication with transpose
Mar
31
answered Parametric representation of a plane cut of a sphere at y=5