1 | initial version |

`plot(lambda u:1, (-2, 2))`

plots an *horizontal* line where `y`

is constant (i. e. $y=1$).

Do you want a *vertical* line, where the same value of `x`

of `x`

corresponds to (infinitely) many values of `y`

? This by definition *cannot* be the representation of a function of `x`

.

You can use a parametric representation of such a vertical line ; for example, `parametric_plot([1,lambda u:u],(0,2))`

will plot the vertical segment from `(1,0)`

to `(1,2)`

.

You can also directly use the primitive `line`

: `line([(1,0),(1,2)])`

will get the same result as before.

There are probably other ways, whose search is left to you as an exercise...

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