# Ex 9.3, 9 - Chapter 9 Class 12 Differential Equations (Term 2)

Last updated at Dec. 10, 2019 by Teachoo

Ex 9.3

Ex 9.3, 1
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Ex 9.3, 2 Deleted for CBSE Board 2022 Exams

Ex 9.3, 3 Important Deleted for CBSE Board 2022 Exams

Ex 9.3, 4 Deleted for CBSE Board 2022 Exams

Ex 9.3, 5 Important Deleted for CBSE Board 2022 Exams

Ex 9.3, 6 Deleted for CBSE Board 2022 Exams

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Ex 9.3, 9 Deleted for CBSE Board 2022 Exams You are here

Ex 9.3, 10 Important Deleted for CBSE Board 2022 Exams

Ex 9.3, 11 (MCQ) Deleted for CBSE Board 2022 Exams

Ex 9.3, 12 (MCQ) Important Deleted for CBSE Board 2022 Exams

Chapter 9 Class 12 Differential Equations (Term 2)

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Last updated at Dec. 10, 2019 by Teachoo

Ex 9.3, 9 Form the differential equation of the family of hyperbolas having foci on 𝑥−𝑎𝑥𝑖𝑠 and center at origin. Equation of hyperbola having foci on x-axis & center at origin (0, 0) is 𝑥^2/𝑎^2 −𝑦^2/𝑏^2 =1 ∴ Differentiating Both Sides w.r.t. 𝑥 𝑑/𝑑𝑥 [𝑥^2/𝑎^2 −𝑦^2/𝑏^2 ]=𝑑(1)/𝑑𝑥 1/𝑎^2 [2𝑥]−1/𝑏^2 [2𝑦 . 𝑑𝑦/𝑑𝑥]=0 2𝑦/𝑏^2 . 𝑦′=2𝑥/𝑎^2 Since it has two variables, we will differentiate twice 𝑦/𝑏^2 𝑦′=𝑥/𝑎^2 (𝑦/𝑥)𝑦′=𝑏^2/𝑎^2 (𝑦𝑦^′)/𝑥 = 𝑏^2/𝑎^2 Again differentiating both sides w.r.t. x ((𝑦𝑦^′ )^′ 𝑥 − (𝑑𝑥/𝑑𝑥)(𝑦𝑦^′ ))/𝑥^2 =0 (𝑦𝑦^′ )^′ 𝑥 − (1)(𝑦𝑦^′ )=𝟎×𝒙^𝟐 (𝑦𝑦^′ )^′ 𝑥 −𝑦𝑦^′=𝟎 (𝒚𝒚^′ )^′ 𝑥 −𝑦𝑦^′=0 (Using Quotient rule and Diff. of constant is 0) (𝒚^′ 𝒚^′+𝒚𝒚′′)𝑥 −𝑦𝑦^′=0 (〖𝑦^′〗^2+𝑦𝑦′′)𝑥 −𝑦𝑦^′=0 𝑥〖𝑦^′〗^2+𝑥𝑦𝑦^′′−𝑦𝑦^′=0 𝒙𝒚𝒚^′′+𝒙〖𝒚^′〗^𝟐−𝒚𝒚^′=𝟎 (Using Product rule)