Ode45 returns NaN, Why?

Question

Halil 2018-4-4

0
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https://ww2.mathworks.cn/matlabcentral/answers/392696-ode45-returns-nan-why

评论： Halil 2018-4-5

采纳的回答： Torsten

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Having a system of three odes

I put the odes in a function and the script to solve the given function

I'm getting NaN for output of ode45

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

function dx=funF7(t,x)
ft_to_m=0.3048; 
lb_to_kg=0.45359273;
S=213.8264*ft_to_m^2;          
m=22900*lb_to_kg;             
CD=1.34721248450636;           
CL=0.387532621392346;          
phi1=0;
rho_0=1.226;                   
beta=0.1387/1000;              
R_Earth=6378000;               
%State variables
r=x(1);
V=x(2);
gamma=x(3);
h=r-R_Earth;                   
rho=rho_0*exp(-beta*h);         
%Nonlinear equations with recpect to time
q=(V^2*rho)/2;                
L=q*S*CL/m;                    
D=q*S*CD/m;                    
%Equations of motion
dx=zeros(3,1);                
dx(1)=V*sin(gamma);
dx(2)=-D/cos(phi1) - sin(gamma)/r^2;
dx(3)=L/V + V*cos(gamma)/r - cos(gamma)/r^2/V;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

Solver

clc; clear all 
step_size1=0.0004;
r0=0.3256;
V0=2.4741;
gamma0=-0.1027;
x0=[r0  V0  gamma0];
tspan=[0    0.1];
options = odeset('MaxStep',step_size1);
[tt xx]= ode45(@funF7,tspan,x0,options);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%