how to Solve differential equation

Hi all

I have equation like this

dy/dt = a*y^2 + b*y + c

where a, b and c are constant

how can I solve this equation using matlab

Answer 1

[Star Strider]

I would use ode45 (unless your constants vary significantly in magnitude, then use ode15s).

The code:

a = 0.1;                                    % Create Data
b = 0.2;                                    % Create Data
c = 0.3;                                    % Create Data

f = @(t,y) a.*y.^2 + b.*y + c;              % Differential Equation Anonymous Function

tspan = [0 5];                              % Time Span
y0 = 0;                                     % Initial Condition

[t,y] = ode45(f, tspan, y0);                % Numerically Integrate ‘f(y)’

figure(1)
plot(t,y)
grid

See the documentation for ode45 for details.

[jone]

Thank you Star Strider for your answer it is helpful

[Star Strider]

My pleasure.

[siddharth tripathi]

Its amazing star. I am going around looking at your solutions and liking them. LOl

[Star Strider]

Thank you very much!

Answer 2

[arbia haded]

i would like to ask 2 quetions plz : 1- with ode45 can we solve a differential equation with spatial variation, for example the variation in the cartisian frame (x, y and z) 2- with ode45 can we solve a system like: dEz/dy-dEy/dz = a dEx/dz-dEz/dx = b dEy/dx-dEx/dy = c

i will be thankful if some one can help me

[Torsten]

No. ode45 solves ordinary differential equations.

What you have is a system of partial differential equations.

Best wishes

Torsten.