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महाराष्ट्र राज्य शिक्षण मंडळएचएससी वाणिज्य (इंग्रजी माध्यम) इयत्ता १२ वी

Xy dydx =x2+2y2

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प्रश्न

`xy dy/dx  = x^2 + 2y^2`

बेरीज
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उत्तर

`xy  dy/dx  = x^2 + 2y^2`

∴ `dy/dx = x^2 + (2y^2)/ (xy)`  …(i)

Put y = tx  ...(ii)

Differentiating w.r.t. x, we get

`dy/dx = t + x dt/dx`  ...(iii)

Substituting (ii) and (iii) in (i), we get

`t + x dt/dx = (x^2 + 2t^2 x^2)/ (x(tx))`

∴ `t + x dt/dx = (x^2 (1+2t^2))/(x^2t)`

∴ `x dt/dx (1+2t^2)/t - t = (1+ t^2)/t`

∴ `t/(1+t^2) dt = 1/x dx`

Integrating on both sides, we get

`1/2 int (2t)/(1+t^2)  dt = int dx/x`

∴ `1/2 log|1 + t^2| = log |x| + log |c|`

∴ log |1 + t2 | = 2 log |x| + 2log |c|

= log |x2 | + log |c2|

∴ log |1 + t2 | = log |c2 x2|

∴ 1 + t2 = c2x2

∴ `1 + y^2/x^2 = c^2x^2`

∴ x2 + y2 = c2 x4

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पाठ 8: Differential Equation and Applications - Miscellaneous Exercise 8 [पृष्ठ १७३]

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बालभारती Mathematics and Statistics 1 (Commerce) [English] Standard 12 Maharashtra State Board
पाठ 8 Differential Equation and Applications
Miscellaneous Exercise 8 | Q 4.13 | पृष्ठ १७३

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