how can i verificate the forward kinematic in my 2d robotic arm?

hi! i have made a robotic arm 2dof and my code is:

function [] = ServoAngle(Theta1,Theta2)

L1=0.065;%m
L2=0.125;%m

a=arduino('COM4');
servoAttach(a,9);
servoAttach(a,10);

px=L2*cos(Theta1+Theta2) + L1*cos(Theta1)
py=L2*sin(Theta1+Theta2) + L1*sin(Theta1)

servoWrite(a,9,Theta1);
servoWrite(a,10,Theta2);

plot(px,py,'r.');
xlabel('Px','fontsize',10);
ylabel('Py','fontsize',10);
pause(1);
end

px,py are coordinates of gripper, so im giving angles in 2 servos and i want to see if gripper goes in the correct py,py coordinates, how can i do this?