/NumPy 1.17

# numpy.polynomial.chebyshev.cheb2poly

`numpy.polynomial.chebyshev.cheb2poly(c)` [source]

Convert a Chebyshev series to a polynomial.

Convert an array representing the coefficients of a Chebyshev series, ordered from lowest degree to highest, to an array of the coefficients of the equivalent polynomial (relative to the “standard” basis) ordered from lowest to highest degree.

Parameters: `c : array_like` 1-D array containing the Chebyshev series coefficients, ordered from lowest order term to highest. `pol : ndarray` 1-D array containing the coefficients of the equivalent polynomial (relative to the “standard” basis) ordered from lowest order term to highest.

#### Notes

The easy way to do conversions between polynomial basis sets is to use the convert method of a class instance.

#### Examples

```>>> from numpy import polynomial as P
>>> c = P.Chebyshev(range(4))
>>> c
Chebyshev([0., 1., 2., 3.], domain=[-1,  1], window=[-1,  1])
>>> p = c.convert(kind=P.Polynomial)
>>> p
Polynomial([-2., -8.,  4., 12.], domain=[-1.,  1.], window=[-1.,  1.])
>>> P.chebyshev.cheb2poly(range(4))
array([-2.,  -8.,   4.,  12.])
```

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https://docs.scipy.org/doc/numpy-1.17.0/reference/generated/numpy.polynomial.chebyshev.cheb2poly.html