You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: airfoilAnalytic0515AlCd.m
    path of file: ./repos/LADAC/aerodynamics/airfoil/analytic/analytic_05_15_alpha
    
    the code of the file until where you have to start completion: function c_D = airfoilAnalytic0515AlCd(fcd,alpha)
% airfoilAnalytic0515AlCd is an analytic function for the drag coefficient
% w.r.t. angle of attack / alpha (Al).
%   It returns good results in for angles of attack between -5 deg and 15
%   deg (0515).
%   This function can compute N airfoils/conditions at once.
% 
% Inputs:
%   fcd         analytic function parameters array (see outputs of
%               airfoilAnalytic0515AlFit)
%   alpha       angle of attack (1xN array), in deg
% 
% Outputs:
%   c_D         drag coefficient (1xN array)
% 
% Literature:
%   [1] https://arc.aiaa.org/doi/pdfplus/10.2514/1.C034910

% Disclamer:
%   SPDX-License-Identifier: GPL-3.0-only
% 
%   Copyright (C) 2020-2022 Yannic Beyer
%   Copyright (C) 2022 TU Braunschweig, Institute of Flight Guidance
% *************************************************************************

filter = 0.5 + 0.5*tanh( fcd(4,:) .* (pi/90*(alpha-fcd(5,:)) ) );

    
function c_D = airfoilAnalytic0515AlCd(fcd,alpha)
% airfoilAnalytic0515AlCd is an analytic function for the drag coefficient
% w.r.t. angle of attack / alpha (Al).
%   It returns good results in for angles of attack between -5 deg and 15
%   deg (0515).
%   This function can compute N airfoils/conditions at once.
% 
% Inputs:
%   fcd         analytic function parameters array (see outputs of
%               airfoilAnalytic0515AlFit)
%   alpha       angle of attack (1xN array), in deg
% 
% Outputs:
%   c_D         drag coefficient (1xN array)
% 
% Literature:
%   [1] https://arc.aiaa.org/doi/pdfplus/10.2514/1.C034910

% Disclamer:
%   SPDX-License-Identifier: GPL-3.0-only
% 
%   Copyright (C) 2020-2022 Yannic Beyer
%   Copyright (C) 2022 TU Braunschweig, Institute of Flight Guidance
% *************************************************************************

filter = 0.5 + 0.5*tanh( fcd(4,:) .* (pi/90*(alpha-fcd(5,:)) ) );
% own formula
c_D = fcd(1,:) ...
    + fcd(2,:) .* powerFast(alpha-fcd(3,:),2) .* ( 1 - filter ) ...
    + filter .* fcd(6,:) .* sin(pi/180*alpha);

end