second order differential systems of a non linear ODE

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Lewis Fer 2021-6-17

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评论： Lewis Fer 2021-6-19

Considering theth differential system equations to be solved are:

f''(t) = 3*f(t)*g(t) + 5 g''(t) = 4*g(t)*f(t) + 7 with initial conditions: f(0) = 1.5, g'(0) = 0 and boundary constraints tf = 1: g(1) = 3, f'(1) =q* f(1)

With q is natural number

how we can plot the solution satysfying the boundary conditions

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Lewis Fer 2021-6-19

I want solve this problem for each natural number that we want to test some results about the Effect when we have q <10 and q>10 fo rexample ?

Can you show me how to do it for a general case of a given natural number?

in mathematic can we replace : f'(1) =2* f(1) by f'(1)=2*exp(2) ?

Lewis Fer 2021-6-19

in mathematic can we replace : f'(1) =q* f(1) by f'(1)=q*exp(q) ? because the solution of the differential equation

f'(x) =q* f(x) has the forme f(x)=C*exp(qx) and I know tha C in our case equal=1

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回答（1 个）

Sulaymon Eshkabilov 2021-6-19

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在 MATLAB Online 中打开

Small typo err in your code:

xmesh = linspace(0,1,10);
sol = bvpinit(xmesh, @iguess);
sol = bvp5c(@odefcn,@bcfcn,sol,bvpset('RelTol ' ,1e-13 ,'AbsTol ',1e-13,'Nmax ',6000)); % ERR: No space after: 'RelTol', 'AbsTol', 'Nmax' 