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Please Solve RD Sharma Class 12 Chapter 21 Differential Equation Exercise 21.10 Question 33 Maths Textbook Solution.

Answers (1)

Answer:  y=\left(\frac{x^{2}}{2}+C\right) e^{x}

Hint: To solve this equation we use \frac{d y}{d x}+P y=Q  where P,Q  are constants.

Give:  \begin{aligned} &\frac{d y}{d x}-y=x e^{x} \\ & \end{aligned}

Solution:  \frac{d y}{d x}+(-1) y=x e^{x}

\begin{aligned} &=\frac{d y}{d x}+P y=Q \\ &P=-1, Q=x e^{x} \end{aligned}


If  of differential equation is

\begin{aligned} &I f=e^{\int P d x} \\ & \end{aligned}

=e^{\int-1 d x} \\

=e^{-\int d x} \\

=e^{-x} \\

y I f=\int Q I f d x+C \\

=y\left(e^{-x}\right)=\int x e^{x} e^{-x} d x+C

\begin{aligned} &=y\left(e^{-x}\right)=\int x e^{x-x} d x+C \\ & \end{aligned}

=y\left(e^{-x}\right)=\int x e^{0} d x+C \\

=y\left(e^{-x}\right)=\int x d x+C \\

=y\left(e^{-x}\right)=\frac{x^{1+1}}{1+1}+C \\


\begin{aligned} &=y\left(e^{-x}\right) e^{x}=e^{x}\left(\frac{x^{2}}{2}+C\right) \\ & \end{aligned}

=y\left(e^{-x+x}\right)=e^{x}\left(\frac{x^{2}}{2}+C\right) \\

=y\left(e^{0}\right)=e^{x}\left(\frac{x^{2}}{2}+C\right) \\


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