_L_i_n_e_a_r_l_y _I_n_t_e_r_p_o_l_a_t_i_n_g _F_u_n_c_t_i_o_n_s
	
	     approxfun(x, y, method="linear", rule=1)
	
	_A_r_g_u_m_e_n_t_s:
	
	         x,y : vectors giving the coordinates of the points
	               to be interpolated.  Alternatively a single
	               plotting structure can be specified.
	
	        xout : an optional set of values specifying where
	               interpolation is to take place.
	
	      method : this specifies the interpolation method to be
	               used.  Currently this is ignored and linear
	               interpolation is always used.
	
	        rule : an integer describing how interpolation is to
	               take place outside the interval
	               [min(x),max(x)].  If rule is 1 then NAs are
	               returned for such points and if it is 2, the
	               value at the closest data extreme is used.
	
	_V_a_l_u_e:
	
	     A function which will perform linear interpolation of
	     the given data points.  For a given set of x values
	     this function will return the corresponding interpo-
	     lated values.  This is often more useful than approx.
	
	_S_e_e _A_l_s_o:
	
	     approx, spline, splinefun.
	
	_E_x_a_m_p_l_e_s:
	
	     x <- 1:10
	     y <- rnorm(10)
	     f <- approxfun(x, y)
	     curve(f(x), 0, 10)