MATLAB: I need help on how to plot the max y peak on two different lines on one plot

y peak plotting

thank you for any help in adavnce. 
% This program computes three projectiles motion, velocity, and accleration of a sphere with and without
%air resistance
clear;
close all;
clc
%% Sphere soccer ball 
rad =  0.037;   % sphere radius
mass = 0.147;  % mass spherekg    
Cd = 0.47;     % Drag coefficient
Af = pi*rad^2;  % cross section area sphere
%% air density Gravitiy
rho = 1.2;   % air density
g = 9.81;     % gravitational acceleration  
%% Initial condition: position and velocity
yo = 2;     % initial position
V1 = 15;      % initial velocity
xo = 0;       %intial position  
d=45 ;           %degreess
theta = d*pi/180; 
%% Time vector and time step
dt = 0.1;    % time step
t = 0:dt:10;  % time vector
imax = length(t);
%% Velocity and position no drag
acc1 = -g;               % acceleration with no drag
x = V1*t*cos(theta); % position no drag
y = V1*t*sin(theta)- 0.5*g*t.^2;                                             
vx  = V1 * cos(theta); % velocity no drag
vy = V1 * sin(theta)-0.5*g*t.^2;
V1 = sqrt(vx^2 +vy.^2);
%% terminal velocity with drag
Vter = sqrt(mass*g/(0.5*Cd*rho*Af));  
%% Acceleration velocity and position with drag
%% Pre set
accx2 = zeros(size(t)); % initialize acceleration with drag
accy2 = zeros(size(t));
Fdx = zeros(size(t));   % initialize force with drag
Fdy = zeros(size(t));
Vx2 = zeros(size(t));   % initialize velocity with drag
Vy2 = zeros(size(t));
V2  = zeros(size(t));
y2 = zeros(size(t));   % initialize position with drag
x2 = zeros(size(t));
% Initialize previous state
yprv = y;  % initialize previous position (initial condition)
xprv = x;
Vxprv = vx;  % initialize previous velocity (initial condition)
Vyprv = vy;
%%  loop drag force, acceleration, velocity and position
for i=1:imax  
    Fdx(i) = 0.5.*Cd.*rho.*Af.*Vxprv.^2;    % Drag force  
    Fdy(i) = 0.5.*Cd.*rho.*Af.*Vyprv(i).^2;
    accx2(i) = -Fdx(i)/mass*V2(i).*Vx2(i) ;        % Acceleration                       
    accy2(i) =-g - Fdy(i)/mass*V2(i).*Vy2(i) ;                                              
     V2(i)=sqrt(Vx2(i).^2+Vy2(i).^2);    
    Vx2(i) = Vxprv + accx2(i)*dt;       % Velocity 
    Vy2(i) = Vyprv(i) + accy2(i)*dt;    
    x2(i) = xprv(i) + Vx2(i)*dt+0.5*accx2(i)*dt.^2;
    y2(i) = yprv(i) + Vy2(i)*dt+0.5*accy2(i)*dt.^2;         % Position  
    yprv(i) = y2(i);                   % Update previous position 
    xprv(i) = x2(i);
    Vxprv = V2(i);                   % Update previous velocity
    Vyprv(i) = V2(i);
end
    %% drag no drag
    figure(1)
    plot(x,y,'b:'), hold on
    plot(x2,y2,'g'),

Best Answer

[maxy, maxyidx] = max(y);
[maxy2, maxy2idx] = max(y2);
plot(x(maxyidx), maxy, 'b^');
plot(x2(maxy2idx), maxy2, 'g^');
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