### 27.11.3 Checking whether lines and/or planes in space are parallel

See Section 26.15.11 for checking for parallels in 2D geometry.

The is_parallel command determines if two objects are parallel.

- is_parallel takes two arguments: L,P, each one either a line or a plane.
- is_parallel(L,P) returns 1 if L and P are parallel and 0 otherwise.

#### Examples

L1,L2:=line([0,0,0],[-1,-1,-1]),line([2,3,-2],[-1,-1,-1]); is_parallel(L1,L2)

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P:=plane([-1,-1,-1],[1,2,-3],[0,0,0]); is_parallel(P,L2)

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P1,P2:=plane([0,0,0],[1,2,-3],[1,1,-2]),plane([1,1,0],[2,3,-3],[2,2,-2]); is_parallel(P1,P2)

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