_M_i_s_c_e_l_l_a_n_e_o_u_s _M_a_t_h_e_m_a_t_i_c_a_l _F_u_n_c_t_i_o_n_s
	
	     abs(x)
	     sqrt(x)
	
	_D_e_s_c_r_i_p_t_i_o_n:
	
	     These functions compute miscelaneous mathematical func-
	     tion.  The naming follows the standard for computer
	     languages such as C or Fortran.
	
	_S_e_e _A_l_s_o:
	
	     Arithmetic.
	
	_E_x_a_m_p_l_e_s:
	
	     xx <- -9:9
	     plot(xx, sqrt(abs(xx)),  col = "red")
	     lines(spline(xx, sqrt(abs(xx)), n=101), col = "pink")