@@ -33,27 +33,27 @@ Construct a polynomial from an array (a vector) of its coefficients, lowest orde
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``` julia
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julia> Polynomial ([1 ,0 ,3 ,4 ])
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- Polynomial (1 + 3 x ^ 2 + 4 x ^ 3 )
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+ Polynomial (1 + 3 * x ^ 2 + 4 * x ^ 3 )
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```
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Optionally, the variable of the polynomial can be specified.
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``` julia
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julia> Polynomial ([1 ,2 ,3 ], :s )
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- Polynomial (1 + 2 s + 3 s ^ 2 )
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+ Polynomial (1 + 2 * s + 3 * s ^ 2 )
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```
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Construct a polynomial from its roots.
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``` julia
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julia> fromroots ([1 ,2 ,3 ]) # (x-1)*(x-2)*(x-3)
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- Polynomial (- 6 + 11 x - 6 x ^ 2 + x^ 3 )
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+ Polynomial (- 6 + 11 * x - 6 * x ^ 2 + x^ 3 )
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```
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Evaluate the polynomial ` p ` at ` x ` .
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``` julia
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- julia> p = Polynomial ([1 , 0 , - 1 ])
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+ julia> p = Polynomial ([1 , 0 , - 1 ]);
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julia> p (0.1 )
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0.99
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```
@@ -64,35 +64,44 @@ Methods are added to the usual arithmetic operators so that they work on polynom
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``` julia
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julia> p = Polynomial ([1 ,2 ])
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- Polynomial (1 + 2 x)
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+ Polynomial (1 + 2 * x)
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+
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+ julia> q = Polynomial ([1 , 0 , - 1 ])
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+ Polynomial (1 - x^ 2 )
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+
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+ julia> p - q
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+ Polynomial (2 * x + x^ 2 )
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+
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+ julia> p = Polynomial ([1 ,2 ])
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+ Polynomial (1 + 2 * x)
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julia> q = Polynomial ([1 , 0 , - 1 ])
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Polynomial (1 - x^ 2 )
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julia> 2 p
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- Polynomial (2 + 4 x )
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+ Polynomial (2 + 4 * x )
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julia> 2 + p
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- Polynomial (3 + 2 x )
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+ Polynomial (3 + 2 * x )
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julia> p - q
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- Poly ( 2 x + x^ 2 )
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+ Polynomial ( 2 * x + x^ 2 )
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julia> p * q
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- Polynomial (1 + 2 x - x^ 2 - 2 x ^ 3 )
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+ Polynomial (1 + 2 * x - x^ 2 - 2 * x ^ 3 )
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julia> q / 2
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- Polynomial (0.5 - 0.5 x ^ 2 )
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+ Polynomial (0.5 - 0.5 * x ^ 2 )
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- julia> q ÷ p # `div`, also `rem` and `divrem`
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- Polynomial (0.25 - 0.5 x )
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+ julia> q ÷ p # `div`, also `rem` and `divrem`
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+ Polynomial (0.25 - 0.5 * x )
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```
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Operations involving polynomials with different variables will error.
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``` julia
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- julia> p = Polynomial ([1 , 2 , 3 ], :x )
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- julia> q = Polynomial ([1 , 2 , 3 ], :s )
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+ julia> p = Polynomial ([1 , 2 , 3 ], :x );
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+ julia> q = Polynomial ([1 , 2 , 3 ], :s );
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julia> p + q
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ERROR: Polynomials must have same variable.
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```
@@ -105,18 +114,18 @@ degree of `p` (for a nonzero polynomial).
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``` julia
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julia> integrate (Polynomial ([1 , 0 , - 1 ]))
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- Polynomial (x - 0.3333333333333333 x ^ 3 )
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+ Polynomial (1.0 * x - 0.3333333333333333 * x ^ 3 )
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julia> integrate (Polynomial ([1 , 0 , - 1 ]), 2 )
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- Polynomial (2.0 + x - 0.3333333333333333 x ^ 3 )
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+ Polynomial (2.0 + 1.0 * x - 0.3333333333333333 * x ^ 3 )
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```
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Differentiate the polynomial ` p ` term by term. The degree of the
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resulting polynomial is one lower than the degree of ` p ` .
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``` julia
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julia> derivative (Polynomial ([1 , 3 , - 1 ]))
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- Polynomial (3 - 2 x )
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+ Polynomial (3 - 2 * x )
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```
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### Root-finding
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