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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def rotate_in_plane(chi, phase):
 """For transforming spins between the coprecessing and coorbital frames"""

    v = chi.T
    sp = np.sin(phase)
    cp = np.cos(phase)
    res = 1.*v
    res[0] = v[0]*cp + v[1]*sp
    res[1] = v[1]*cp - v[0]*sp
    return res.T