def u_func(c,h,phi=0.3): # equation 1
    """ 
    Equation (1) from the sheet (a Cobb-Douglas util func)
    Returns utility from consumption and housing

    Arguments:
    c:      consumption
    h:      housing
    phi:    preferences (default 0.3)

    """
    u = (c**(1-phi))*(h**phi)
    return u