Homogeneous linear equations geometrically

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A homogeneous linear equation in three variables, expressed as ax + by + cz = 0, represents a geometric plane in three-dimensional space. If all coefficients a, b, and c are zero, the solution set encompasses all points in space. When at least one coefficient is non-zero, the equation defines a specific plane determined by the relationships among the variables. The solutions can be rearranged to express one variable in terms of the others, illustrating the plane's orientation. Understanding these equations is crucial for visualizing linear relationships in higher dimensions.
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what does a homogeneous linear equation in 3 variables represent geometrically ?
 
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A plane
 
A homogeneous linear equation is of the form ax+ by+ cz= 0 for numbers a, b, c, d. If all of a, b, c, d are 0, that is true for all (x, y, z) so the solution set is all space.

If any of a, b, c, is not 0, we can solve for that variable:
x= (-by- cz)/a
y= (-ax- cz)/b
z= (-ax- by)/c
which are planes,
 
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Seemingly by some mathematical coincidence, a hexagon of sides 2,2,7,7, 11, and 11 can be inscribed in a circle of radius 7. The other day I saw a math problem on line, which they said came from a Polish Olympiad, where you compute the length x of the 3rd side which is the same as the radius, so that the sides of length 2,x, and 11 are inscribed on the arc of a semi-circle. The law of cosines applied twice gives the answer for x of exactly 7, but the arithmetic is so complex that the...
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