Need Help Transcribing differential equations in to Matlab code
信息
此问题已关闭。 请重新打开它进行编辑或回答。
显示 更早的评论
I am trying to transcribe the following differential equation that describes a falling body:
dy/dt=mg/K (1-e^(-K/m t)) (with air resistance)
dy/dt=gt (without air resistance)
I would like to create a function and then call the function using ode45 and then plot a graph. I am still trying to get a good handle of matlab, but I have not been successful.
0 个评论
回答（2 个）
Fabricio Castro
2018-7-7
Hi JB
Your problem is kind of simple to solve. With the following code you will achieve what you want:
%Supose you may want to use a time interval of [0,3] with an initial
%condition y0 equal to 50 meters
timeInterval = linspace(0,3,51);
y0 = 50;
%Defining parameters like mass (m), air resistance (K), and gravity (g)
m = 5;
K = 2;
g = 9.8;
%Using ode45 function to solve the falling body equation
[t,y] = ode45(@(t,y) (m*g)/(K*(1-exp(-K/(m*t)))), timeInterval, y0);
%Plot the result
figure
subplot(1,2,1)
plot(t,((m.*g)./(K.*(1-exp(-K./(m.*t))))),'-bo')
xlabel('time')
ylabel('dy/dt')
title('ODE graph')
set(gca,'FontSize',18)
subplot(1,2,2)
plot(t,y,'-ro')
xlabel('time')
ylabel('y')
title('Solution graph')
set(gca,'FontSize',18)
Thanks
2 个评论
Star Strider
2018-7-7
@Fabricio Castro — We do not supply complete code to homework problems here on MATLAB Answers. The OP must demonstrate an effort. We will then help to get the posted code running.
JB
2018-7-7
Star Strider
2018-7-7
0 个投票
The syntax of your function is correct. However you need to spend some time with the documentation.
For future reference, see the documentation on Anonymous Functions (link), and Vectorization (link).
0 个评论
此问题已关闭。
关闭：
2021-8-20
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
