<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def sky2pix_vec(self, pos, r, pa):
 """ Convert a vector from sky to pixel coords. The vector has a magnitude, angle, and an origin on the sky. Parameters pos : (float, float) The (ra, dec) of the origin of the vector (degrees). r : float The magnitude or length of the vector (degrees). pa : float The position angle of the vector (degrees). Returns ------- x, y : float The pixel coordinates of the origin. r, theta : float The magnitude (pixels) and angle (degrees) of the vector. """

        ra, dec = pos
        x, y = self.sky2pix(pos)
        a = translate(ra, dec, r, pa)
        locations = self.sky2pix(a)
        x_off, y_off = locations
        a = np.sqrt((x - x_off) ** 2 + (y - y_off) ** 2)
        theta = np.degrees(np.arctan2((y_off - y), (x_off - x)))
        return x, y, a, theta