analytic solution of an iterative equations

1 次查看（过去 30 天）

Metin 2014-3-17

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/121965-analytic-solution-of-an-iterative-equations

评论： Metin 2014-3-17

Hello, my question is about a unique solution of nonlinear iterative function in Matlab, to be more clear the function that I am looking for is function of time which is initial 0

if true
f(t=0)=0
f'(t)=A/B                % is known, 
(A-k.*f(t))/B.*t = f(t)  %here A, B k is also known 
f(t)=A/B.*t       %f(t) is linear function of time 't' without k, but in actual case k exists              
end

for variables A,B,k, I want to find out specific time when f(t)=2, with respect to known parameters, thanks for any suggestions in advance...

4 个评论
显示 2更早的评论隐藏 2更早的评论

Walter Roberson 2014-3-17

在 MATLAB Online 中打开

To get the expression involving k to work,

f(t) = A*B/(k*t+B)^2

which simplifies to f(t) = A/B when k is 0 -- which is different than f'(t) = A/B . Perhaps you wanted

(A-k.*f(t))/B.*t = f'(t)

Metin 2014-3-17

在 MATLAB Online 中打开

Hi, in fact no,

(A-k.*f(t))/B.*t = f(t)

is right, question arises to calculate power losses of a mosfet in conduction mode, here mosfet on state resistance value is constant k, but during on state current is a linear function of time such

f(t)=A/B.*t

without voltage drop on mosfet, but as voltage drop is also function of current (time), which is:

k.*f(t)

for that reason current is not actually linear any more by the time it is increasing, but the voltage drop on mosfet as well, in simulink with feedback it is easy to find out time needed to reach a specific value of current but I have to calculate rise time in matlab m.file,that is reason trying to solve such problem, thanks for comment

请先登录，再进行评论。

请先登录，再回答此问题。