Pressure calculation loop error

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John Woods 2020-6-26

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https://ww2.mathworks.cn/matlabcentral/answers/554965-pressure-calculation-loop-error

评论： John Woods 2020-6-26

I have to calculate the pressure at different altitudes. I have the code that calculate all of the variables to go into my pressure calculation and all of those run fine and seem to produce the values that I am looking for but when I try to run the pressure loop it says the sides have different values. Can anyone tell me where I am going wrong?

This is what I have so far:

clc;
clear all;
p(1)=1.013e5;
r=287;                               %Jules/kg*K
dz=200;
% =================== Gravity Calculations ============================
alt=0:200:50000;
Re=6.37e6;
g0=9.80665;
i=1:length(alt);
g=g0*((Re^2)./((alt(i)+Re).^2));
% =================== Temperature Calculations ============================
for i=1:length(alt)
    if alt(i)<=11000
        t(i)=((-71.5/11000).*alt(i)+15)+273;
    elseif 11000<alt(i) && alt(i)<=20100
        t(i)=(-56.5)+273;
    elseif 20100<alt(i) && alt(i)<=32200
        t(i)=((12/12100).*alt(i)-76.434)+273;
    elseif 32200<alt(i) && alt(i)<=47300
        t(i)=((42/15100).*alt(i)-134.063)+273;
    else
        t(i)=(-2.5)+273;
    end
    
    x=g./(r*t(i));
     
end
for i=1:length(alt)
    p(i+1)=p(i).*((1/2)*x.*dz)+(1-(1/2)*x.*dz);
end