Question: what is issue in thus odes which not make my function to be zero?

I test a lot of them but some of them make a problem i  don't know i am do it in wrong way or the author did wrong i need verifying thus solution of odes specially in case 4 when we have not equal sign how use that?

and case 5 is Weierstrass elliptic function which i don't know how set up and use i think is a on kinf of odes but why they use that sign for this function?

ode-17.mw

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