How to go from the explicit form of a straight line to the implicit form?
Hey, could you maybe explain to me in general terms how to get from the explicit representation of the even PQ to the implicit one?
explicit: g: (a,b) + r • (c,d)
implicit: g: ax+by= c
and perhaps then with an example?
g: (1,2) + r • (3,4)
You can consider the explicit form as two equations:
– If c=d=0, you do not have a straight line, but only a point (a, b).
– If c=0 (and d≠0), equation 1. The other equation then only says “no one r, then you will get any y (or x)”.
– For c≠0 and d≠0, you get the implicit equation via d·(1.) − c·(2.):
(drc-crd rises).
For your example, 4×-3y=4.1-3.2=-2 results.
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If you look more closely at the implicit equation, you will see the vector (d, −c) perpendicular to (c, d) and the starting point (a, b). And the implicit equation simply says:
or in vector writing short and crisp: