how to solve attached problem using fsolve and ode45??

i want to solve this in the following manner :

USING FSOLVE

1) calculate x3, x4 from given x1,x2.

2) calculate x5 from x1,x3 and x6 from x1,x3,x5

3) use ODE 45 to calculate x7 and x8 from x5 and x6

4) update x1 and x2 from x7 and x8

5) run this till we reached to desire value of x1 and x2.

Answer 1

[darova]

You need only x7 and x8 initial

function main
[t,x] = ode45(@func,tspan,[x7 x8]);
plot(t,x)
    function dx = func(~,x)
        x1 = x(2)^2 + 3*x(1);
        x2 = x(1) - x(2);
        % x3 .. x6
        dx(1,1) = -x5;
        dx(2,1) = -x6;
    end
end

[chirag patel]

Will it give all x variable answer ??

[darova]

no

[darova]

But you can do this

[t,x] = ode45(@func,tspan,[x7 x8]);
x7 = x(:,1);
x8 = x(:,2);
x1 = x8.^2 - 3*x7;
plot(t,x1)

[chirag patel]

i think i have not stated problem clearly.

i want to solve this in the following manner :

USING FSOLVE

1) calculate x3, x4 from given x1,x2.

2) calculate x5 from x1,x3 and x6 from x1,x3,x5

3) use ODE 45 to calculate x7 and x8 from x5 and x6

4) update x1 and x2 from x7 and x8

5) run this till we reached to desire value of x1 and x2.

[darova]

I don't understand why do you need fsolve. Did you try the code from answer?

[chirag patel]

If I want all variable to solve then how to implement in matlab??

[darova]

DId you read my comments above? DO you understand me?

[chirag patel]

No

[darova]

please?