Exercise 9.3

Which of the following differential equations has y = x as one of its particular solution? $(A)\frac{{{\partial }^{2}}y}{\partial {{x}^{2}}}-{{x}^{2}}\frac{dy}{dx}+xy=x(B)\frac{{{\partial }^{2}}y}{\partial {{x}^{2}}}+{{x}^{{}}}\frac{dy}{dx}+xy=x(C)\frac{{{\partial }^{2}}y}{\partial {{x}^{2}}}-{{x}^{2}}\frac{dy}{dx}+xy=0(D)\frac{{{\partial }^{2}}y}{\partial {{x}^{2}}}+{{x}^{{}}}\frac{dy}{dx}+xy=0$

= 0 – (x2 × 1) + (x × x) = -x2 + x2 = 0

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Form a differential equation representing the given family of curves by eliminating arbitrary constants a and b in \[\mathbf{y}\text{ }=\text{ }{{\mathbf{e}}^{\mathbf{x}}}~\left( \mathbf{a}\text{ }\mathbf{cos}\text{ }\mathbf{x}\text{ }+\text{ }\mathbf{b}\text{ }\mathbf{sin}\text{ }\mathbf{x} \right)\]

Differentiating both sides two times w.r.t.         [By eq. (i)]……….(ii) Again differentiating w.r.t. ,           [By eq. (i)]  

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Form a differential equation representing the given family of curves by eliminating arbitrary constants a and b in \[\mathbf{y}\text{ }=\text{ }\mathbf{a}{{\mathbf{e}}^{\mathbf{3x}}}~+\text{ }\mathbf{b}{{\mathbf{e}}^{-\mathbf{2x}}}\]

DifferentiatING both sides two times w.r.t.    ……….(ii) Again differentiating w.r.t. ,  ……….(iii) Multiplying eq. (i) by 3 and subtracting eq. (ii) from it, we get  ……….(iv) Again multiplying eq....

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Form a differential equation representing the given family of curves by eliminating arbitrary constants a and b in \[{{\mathbf{y}}^{\mathbf{2}}}~=\text{ }\mathbf{a}\text{ }({{\mathbf{b}}^{\mathbf{2}}}~-\text{ }{{\mathbf{x}}^{\mathbf{2}}})\]

Equation of the family of curves  ……….(i) Differentiating both sides two times w.r.t.     ……….(ii) Again differentiating w.r.t. ,   ……….(iii) Putting this value of  in eq. (ii), we get  ...

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