using quiver to create a vector field for an equation with only 1 variable.

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Elijah Jones 2023-6-27

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https://ww2.mathworks.cn/matlabcentral/answers/1988503-using-quiver-to-create-a-vector-field-for-an-equation-with-only-1-variable

评论： Elijah Jones 2023-6-27

I have an equation which i am trying to use quiver to create a vector field for. the equation can be defined as this. yprime = alpha*y - beta*y.^2 - H where H = ((y.^3)*p)./((y.^3)+q) and alpha and beta are constants. so are p and q. everywhere I look though quiver is used to define problems with two equations. is there a way to use it for this equation?

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Answer 1

KSSV 2023-6-27

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https://ww2.mathworks.cn/matlabcentral/answers/1988503-using-quiver-to-create-a-vector-field-for-an-equation-with-only-1-variable#answer_1262943

在 MATLAB Online 中打开

alpha = rand ;
beta = rand ;
p = rand ;
q = rand ;
y = linspace(0,1) ;
yprime = alpha*y - beta*y.^2-(((y.^3)*p)./((y.^3)+q)) ;
dyprime = gradient(yprime) ;
plot(y,yprime)
hold on
quiver(y,yprime,yprime,dyprime)

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Elijah Jones 2023-6-27

编辑：Elijah Jones 2023-6-27

在 MATLAB Online 中打开

alpha = .75 ;
beta = .1 ;
p = 1.5 ;
q = 1.25 ;
y = linspace(0,1) ;
yprime = alpha*y - beta*y.^2-(((y.^3)*p)./((y.^3)+q)) ;
dyprime = gradient(yprime) ;
plot(y,yprime)
hold on
quiver(y,yprime,yprime,dyprime)

this is the stuff i have to put into this equation. it doesn't look correct. if this makes any difference yprime is also dy/dt. differential equation just doesn't have any t's in it. The direction field should though. I'm looking for the slop field that is y(t) using yprime above.

Elijah Jones 2023-6-27