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- (x^2-1)y'+2xy-4x = 0 koja zadovoljava uslov y(2) = 2:
- Prvo podijelis citavu jednacinu sa (x^2-1) i onda ti ostane:
- y' + (2x/x^2-1)*y = 4x/x^2-1
- y=u*v ; u = u(x), v = v(x);
- u'v + uv' + (2x/x^2-1) * uv = 4x/x^2-1
- u'v + u*(v' + 2x/x^2-1 * v) = 4x/x^2-1
- Izjednacimo ovo u zagradi sa nulom i imamo:
- v' = -2x/x^2-1 * v /:v
- v'/v = -2x/x^2-1 / integralimo
- lnv = ln |(x^2-1)^-1| (ovaj integral uradis tako sto uvedes smjenu x^2-1 = t itd.)
- v = 1/x^2-1
- u' * 1/x^2-1 = 4x/x^2-1 / * (x^2-1)
- u' = 4x / integralimo
- u = 2x^2 + c
- y = u*v => (2x^2+c) * 1/x^2-1 ; (x=2)
- 2 = (8+c) * 1/3 = (8+c)/3
- 6 = 8+c => c = -2
- y = (2x^2-2) * 1/x^2-1
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