INDEX EXCEEDS ARRAY BOUNDS

I am plotting NACA airfoil based on the equations. this is the code excerpt where error occurred:

gridPts = 500;
xu = ones(gridPts,1);
yu = ones(gridPts,1);
for i = 1:1:gridPts
   xu(i) = x(i) - yt(i)*sin(theta(i));
   yu(i) = yc(i) + yt(i)*cos(theta(i));
end

Please advise. this is for my class project. I am using 2018a.

[Geoff Hayes]

Kumar - what is the full error message? The problem may be with yt since I don't see anywhere in the code where this variable is intialized. The others appear to be initialized with gridPts so should have the correct dimensions...

Answer 1

[Aquatris]

In your code you have slight mistake, where you forgot to assign to an index but instead overwrite the variable ("(i)" is the fix);

 %Thickness distribution 
 yt = ones(gridPts,1);
 for i = 1:1:gridPts
    yt(i) = 5*T*(a0*sqrt(x(i)) + a1*x(i) + a2*x(i)^2 + a3*x(i)^3 + a4*x(i)^4);
 end