John Eric

Dr. John Eric

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10 years, 348 days

MaplePrimes Activity

These are replies submitted by John Eric

Thank you so much @mmcdara 

@Carl Love Thank you

But what I don't understand why it's working fine in maple 2015 and get stuck in maple 2020?


Thank you so much @Preben Alsholm . 
 I add these two lines and it get stuck again in polarplot, is there anything to add or change?

fcty := RootOf(T, r);

@nm Thank you, I'll look for it

Thank you so much @dharr 

Thank you @Mariusz Iwaniuk


Thank you @Carl Love 

I am exciting to see your answer

Thank you @Preben Alsholm , I like your answer .

But for other equation the singularity will show up , and we can’t change the form of equation , so for that if it's possible  I  need a conditional if to re-solve the equation for example if it's a singularity must return and solve it ( dsolve ) and so that , I hope I have clarified the situation.


Random coefficient


Calculate eng

If eng = singularity

Return and dsolve

Else, end if


thank you 

Thank you @J4James ,

but i steal have probleme whene i change the last condition from 70 to 100 

psi(0.174568e-1) = 100, i get the flowing error ;

Error, (in dsolve/numeric/ComputeSolution) Newton iteration is not converging

best regards 

thank you Mr.@Preben Alsholm 

i will look for other way 

Best regards!


Thank you for your answer Mr.@tomleslie 

i defined the parameters but the problem still not solved 


















equ := arccos(y(t)/R)*R*L*(diff(y(t), `$`(t, 1)))*abs(diff(y(t), `$`(t, 1)))+diff(y(t), `$`(t, 2))+m*sin(E*t+k*R*sin(`θl`));

arccos(y(t))*(diff(y(t), t))*abs(diff(y(t), t))+diff(diff(y(t), t), t)+sin(t+(1-y(t)^2)^(1/2))



fourier(sin(t+(1-y(t)^2)^(1/2)), t, w)+fourier(arccos(y(t))*(diff(y(t), t))*abs(diff(y(t), t)), t, w)-w^2*fourier(y(t), t, w)


csi := y(0) = 0.2e-1, (D(y))(0) = 0;

y(0) = 0.2e-1, (D(y))(0) = 0


sol := dsolve({csi, eq}, numeric, maxfun = 1000000000)

Warning, The use of global variables in numerical ODE problems is deprecated, and will be removed in a future release. Use the 'parameters' argument instead (see ?dsolve,numeric,parameters)


Error, (in solve) cannot solve expressions with fourier(arccos(Y[1])*YP[1]*abs(YP[1]), t, w) for YP[1]




Thank you


thank you for your answer , but it's not work with dsolve 


Good idea 

thanks :)

Thank you very much 

how i can plot these solution ?

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