A math question about projections of lines: Say we have two straight lines which we consider as number lines ([itex]\mathbb{R}[/itex]). I've learned that a projection of one line onto another is of the form [itex]ax + b[/itex] for [itex]a,b\in \mathbb{R}[/itex] when the two lines are parallel. If we allow the possibility that the lines are perpendicular, we have a fractional linear transformation of the form [itex]\frac{ax+b}{cx+d}[/itex].(adsbygoogle = window.adsbygoogle || []).push({});

Now if the lines are neither perpendicular nor parallel, do we still have a fractional linear transformation? I've been trying to build such a projection out of projections I know but with no success.

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# Do projections of lines which are not perpendicular correspond to FLTs?

Can you offer guidance or do you also need help?

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