code: def chebmulx(c):
      """Multiply a Chebyshev series by x.
  
      Multiply the polynomial `c` by x, where x is the independent
      variable.
  
  
      Parameters
      ----------
      c : array_like
          1-D array of Chebyshev series coefficients ordered from low to
          high.
  
      Returns
      -------
      out : ndarray
          Array representing the result of the multiplication.
  
      Notes
      -----
  
      .. versionadded:: 1.5.0
  
      Examples
      --------
      >>> from numpy.polynomial import chebyshev as C
      >>> C.chebmulx([1,2,3])
      array([1. , 2.5, 1. , 1.5])
  
      """
      # c is a trimmed copy
      [c] = pu.as_series([c])
      # The zero series needs special treatment
      if len(c) == 1 and c[0] == 0:
          return c
  
      prd = np.empty(len(c) + 1, dtype=c.dtype)
      prd[0] = c[0] * 0
      prd[1] = c[0]
      if len(c) > 1:
          tmp = c[1:] / 2
          prd[2:] = tmp
          prd[0:-2] += tmp
      return prd
  
imports: import numpy
  import numpy.linalg
  from numpy.core.multiarray import normalize_axis_index
  from .None import polyutils
  from ._polybase import ABCPolyBase
label_desc: Use image node_id 13 for calling a global function with example usage: chebmulx(c) and returns: prd, c