Array indices must be positive integers or logical values.
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Hello everyone, I am new to Matlab and just learning at the moment.
I am trying to calculate a polynomial and then graph it, but I gent an error "Array indices must be positive integers or logical values." on line 23
would appreciate any help
Thank you!
clear
Cd0=0.01
K=0.02
W = 80000
S = 50
q=0.6
dH = 0.1
Hm = 12
H = 0:dH:Hm;
Pol1 = zeros(4,2);
Pol4 = zeros(4,2);
Pol = K*W^2
q = zeros(1,length(H));
q(1) = 1;
for n=2:length(H)
q(n) = (20-dH(n-1))/(20+dH(n-1));
Pol4(n) = Cd0(0.5*1.225*q(n)*50)^2;
Pol1(n) = ((-1.225*q(n))^2*0.5*50);
r =roots([Pol4(n) 0 0 Pol1(n) Pol])
end
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채택된 답변
Bjorn Gustavsson
2020년 6월 3일
Most likely you want to multiply Cd0 with the expression in the parenthesis, you try to index the variable with the value of (0.5*1.225*q(n)*50); Try:
Pol4(n) = Cd0*(0.5*1.225*q(n)*50)^2;
HTH
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추가 답변 (1개)
Hank
2020년 6월 3일
편집: Hank
2020년 6월 3일
In the line:
Pol4(n) = Cd0(0.5*1.225*q(n)*50)^2;
what you wrote says to index Cd0 at 0.5*1.225*q(n)*50, which is probably not an integer. I think you want to multiply by Cd0 like this
Pol4(n) = Cd0 * (0.5*1.225*q(n)*50)^2;
You're also going to have trouble indexing the scalar value like you are: dH(n-1). Maybe you mean H(n-1)?
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Hank
2020년 6월 3일
As I'm continuing to attempt to fix and run the code. More problems are popping up and I'm left wondering what you're trying to simulate here?
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