_L_i_n_e_a_r _I_n_t_e_r_p_o_l_a_t_i_o_n
	
	     approx(x, y, xout, method="linear", n=50, 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.
	
	           n : If xout is not specified, interpolation takes
	               place at n equally spaced points spanning the
	               interval [min(x),max(x)].
	
	        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 list containing n x and y coordinates which linearly
	     interpolate the given data points.
	
	     The function approxfun returns 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 interpolated values.  This is often
	     more useful than approx.
	
	_S_e_e _A_l_s_o:
	
	     approxfun, spline, splinefun.
	
	_E_x_a_m_p_l_e_s:
	
	     x <- 1:10
	     y <- rnorm(10)
	     plot(x, y)
	     points(approx(x, y))