Within the description for the variation of parameters procedure is the restriction:(adsbygoogle = window.adsbygoogle || []).push({});

y1u1' + y2u2' = 0.

Can you explain this restriction, it is not obvious to me, I do not have an explanation where this comes from.

Is it related to

[tex] u[ \frac {dy}{dx} + P(x)y] = 0 [/tex]

from solving first order equations?

Thanks

Sparky_

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# A restriction within Variation of Parameters

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