Error, (in plots/implicitplot) invalid input: the following extra unknowns were found in the input expression
Description
Examples
The implicitplot command computes the two-dimensional plot of an implicitly defined curve.
The invalid input: the following extra unknowns were found in the input expression error occurs when an unknown variable in the first argument is passed to the implicitplot command.
withplots:
Example 1
Lowercase pi is used instead of uppercase Pi.
implicitplotx2+pi⋅y2=1,x=0..1, y=0..1
Error, (in plots/implicitplot) invalid input: the following extra unknowns were found in the input expression: {pi}
Solution:
implicitplotx2+Pi⋅y2=1,x=0..1, y=0..1
Example 2
In the following example, an extra space has been entered between sec and x2 + y2.
implicitplotsec x2+ y2,x=0..1, y=0..1
Error, (in plots/implicitplot) invalid input: the following extra unknowns were found in the input expression: {sec}
Remove the extra space between sec and x2 + y2.
implicitplotsecx2+ y2,x=0..1, y=0..1
Example 3
In the following example, the implicitplot command is used incorrectly to plot an equation in three variables.
implicitplot⁡x+22+y+22+z+22=9,x=−5..5,y=−5..5,z=−5..5
Error, (in plots/implicitplot) invalid input: the following extra unknowns were found in the input expression: {z}
Plot the equation in three variables using the plots[implicitplot3d] command
implicitplot3d⁡x+22+y+22+z+22=9,x=−5..5,y=−5..5,z=−5..5
See Also
plots[implicitplot]
plots[implicitplot3d]
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