Solve the differential equation: ydx+(x-y 2 )dy=0

[Class 12] Solve differential equation: 𝑦𝑑π‘₯ + (π‘₯ βˆ’ y^2)𝑑𝑦 = 0 - CBSE Class 12 Sample Paper for 2023 Boards

part 2 - Question 29 (Choice 1) - CBSE Class 12 Sample Paper for 2023 Boards - Solutions of Sample Papers and Past Year Papers - for Class 12 Boards - Class 12
part 3 - Question 29 (Choice 1) - CBSE Class 12 Sample Paper for 2023 Boards - Solutions of Sample Papers and Past Year Papers - for Class 12 Boards - Class 12

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Question 29 (Choice 1) Solve the differential equation: 𝑦𝑑π‘₯+(π‘₯βˆ’π‘¦^2 )𝑑𝑦=0 For equation 𝑦𝑑π‘₯+(π‘₯βˆ’π‘¦^2 )𝑑𝑦=0 We observe that we cannot use variable separation method Let’s try to put in the form π’…π’š/𝒅𝒙 + Py = Q or 𝒅𝒙/π’…π’š + P1 x = Q1 Now, y dx + (x βˆ’ y2) dy = 0 y dx = βˆ’ (x βˆ’ y2)dy π’…π’š/𝒅𝒙 = (βˆ’π’š)/(π’™βˆ’π’š^𝟐 ) This is not of the form 𝑑𝑦/𝑑π‘₯ + Py = Q Thus, let’s find 𝒅𝒙/π’…π’š 𝑑π‘₯/𝑑𝑦 = (𝑦^2 βˆ’ π‘₯)/𝑦 𝑑π‘₯/𝑑𝑦 = y βˆ’ π‘₯/𝑦 𝒅𝒙/π’…π’š + 𝒙/π’š = y Comparing with 𝒅𝒙/π’…π’š + P1 x = Q1 ∴ P1 = 1/𝑦 &. Q1 = y Finding Integrating factor, IF = 𝑒^∫1▒〖𝑝1 𝑑𝑦〗 = 𝑒^∫1▒𝑑𝑦/𝑦 = 𝒆^π’π’π’ˆβ‘π’š = y Solution is x (IF) = ∫1β–’γ€–(π‘ΈπŸ Γ— 𝑰𝑭)π’…π’š+𝒄〗 π‘₯𝑦=∫1▒〖𝑦 Γ— 𝑦 𝑑𝑦+𝑐〗 π’™π’š= ∫1β–’γ€–π’š^𝟐 π’…π’š+𝒄〗 π’™π’š= π’š^πŸ‘/πŸ‘+π‘ͺ

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science and Computer Science at Teachoo