solving a linear ODE
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how to write in matlab
y = e^ int(75/80)dt
5 个评论
James Tursa
2018-12-12
Please provide more detail. What differential equation are you trying to solve?
Brenda Galabe
2018-12-12
James Tursa
2018-12-12
编辑：James Tursa
2018-12-12
Is it this? (where x1 is a function of time)
d(x1)/dt = -x1 / 2 + 20 * d
What is that d at the end?
Brenda Galabe
2018-12-12
采纳的回答
madhan ravi
2018-12-12
编辑：madhan ravi
2018-12-12
You can verify the result with wolfram but here you will see a C which is constant which arises after antiderivative(without limits):
syms y(t)
ode=diff(y) == exp(75/80)
dsolve(ode)
9 个评论
Brenda Galabe
2018-12-12
madhan ravi
2018-12-12
exp() see edited answer
madhan ravi
2018-12-12
编辑：madhan ravi
2018-12-12
This is how you write the equation:
syms t y
eqn = y == vpa(exp(1)^(int(75/80,t))) % in decimal form
eqn = y == exp(1)^(int(75/80,t)) % in fractions form
madhan ravi
2018-12-12
but the equation looks like this
y = exp^int(75/80)dt . so the exp is before the integral
madhan ravi
2018-12-12
ok cool. answer im getting is
eqn =
y == (3060513257434037/1125899906842624)^((15*t)/16)
i know on paper answer suppose to be exp^(75/80)t
madhan ravi
2018-12-12
Basically they are the same but represented in different forms just substitute the values and see as below:
>> t=1;
>> exp(1)^(75/80)*t
ans =
2.5536
>> (3060513257434037/1125899906842624)^((15*t)/16)
ans =
2.5536
>>
madhan ravi
2018-12-12
ok thank you
madhan ravi
2018-12-12
Anytime :)
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