Graphing a variable function with boundaries problem

Question

Mohsen Nashel 2019-9-24

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/481920-graphing-a-variable-function-with-boundaries-problem

评论： Mohsen Nashel 2019-9-24

i am trying to plot the function that is shown in the picture. Matlab keep giving me the error "Error: File: Q4.m Line: 11 Column: 64

Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for

mismatched delimiters."

Refers to P_0_1 in the loop Screen Shot 2019-09-24 at 12.52.30 PM.png

%Part a)
R=287; % Specific gas constant in J/kg.k
M=[2:0.1:6];
gamma=1.4;
P_0_1=101325; % Pressure at sea level in Pa unit 
for n=1:length(M);
P_0(n,1)=((1+((gamma-1))/2).*M(n).^2).^(gamma/(gamma-1)).*P_0_1);
end
P_0_ratio=P_0./P_0_1;
figure (1) 
plot (M, P_0_ratio)
xlabel('Moch Number')
ylabel('Total stagnation pressure ratio P_0/P_0_1')
title('Total stagnation pressure ratio P_0/P_0_1 vs. Moch Number')
%Part b)
for n=1:length(M);
    delta_s_r(n,1)=-log(P_0_ratio(n));
end
figure(2) 
plot (M,delta_s_r)
xlabel('Moch Number')
ylabel('Dimensionless entropy change \delta s')
title('Dimensionless entropy change \delta s vs. Moch Number')

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Answer 1

Ruger28 2019-9-24

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/481920-graphing-a-variable-function-with-boundaries-problem#answer_393331

编辑：Ruger28 2019-9-24

在 MATLAB Online 中打开

Removing the extra " ) " at the end of that line, yields plots and no errors.

%Part a)
R=287; % Specific gas constant in J/kg.k
M=[2:0.1:6];
gamma=1.4;
P_0_1=101325; % Pressure at sea level in Pa unit 
for n=1:length(M);
P_0(n,1)=((1+((gamma-1))/2).*M(n).^2).^(gamma/(gamma-1)).*P_0_1;
end
P_0_ratio=P_0./P_0_1;
figure (1) 
plot (M, P_0_ratio)
xlabel('Moch Number')
ylabel('Total stagnation pressure ratio P_0/P_0_1')
title('Total stagnation pressure ratio P_0/P_0_1 vs. Moch Number')
%Part b)
for n=1:length(M);
    delta_s_r(n,1)=-log(P_0_ratio(n));
end
figure(2) 
plot (M,delta_s_r)
xlabel('Moch Number')
ylabel('Dimensionless entropy change \delta s')
title('Dimensionless entropy change \delta s vs. Moch Number')