1.

Please solve it anyone​

Answer»

GIVEN :–

• Diffrential EQUATION

\\ \implies \bf(1 + x^2)  \dfrac{dy}{dx} + 2xy = cosx \\

TO FIND :–

• Solution of diffrential equation = ?

SOLUTION :–

\\ \implies \bf(1 + x^2)  \dfrac{dy}{dx} + 2xy = cosx \\

\\ \implies \bf\dfrac{dy}{dx} + \dfrac{2x}{(1 + x^2)}y =  \dfrac{cosx}{(1 + x^2)} \\

COMPARE with –

\\ \implies \bf\dfrac{dy}{dx} +Py =  Q \\

• So –

\\ \implies \bf P =\dfrac{2x}{(1 + x^2)} \:  \: and \:  \: Q = \dfrac{cosx}{(1 + x^2)} \\

• We know that –

\\ \implies \bf I.F. = e^{\int P.dx} \\

\\ \implies \bf I.F. = e^{\int \frac{2x}{(1 + x^2)}dx} \\

\\ \implies \bf I.F. = e^{ \log{(1 + x^2)}} \\

\\ \implies \large{ \boxed{\bf I.F. = 1 +  {x}^{2} }}\\

• Solution :–

\\ \implies \bf y(I.F.) =  \int(I.F)Q.dx + c\\

\\ \implies \bf y(1 +  {x}^{2} ) =  \int\dfrac{cosx}{(1 + x^2)} \times (1 +  {x}^{2}) .dx + c\\

\\ \implies \bf y(1 +  {x}^{2} ) =  \int\cos(x) .dx + c\\

\\ \implies \large { \boxed{\bf y(1 +  {x}^{2} ) =  \sin(x) + c}}\\

is it CORRECT?



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