Differential Equations - Initial Value Problem

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SUMMARY

The discussion focuses on solving the initial value problem defined by the differential equation y' = 7(x^2) + (5y^2) − 6 with the initial condition y(0) = −2. Participants clarify that to find y'(0), one simply substitutes x = 0 and y = -2 into the equation, while higher derivatives like y''(0) can be obtained by differentiating the equation multiple times. The integrating factor mentioned, e^(-5xy), was incorrectly applied, leading to confusion. Ultimately, the correct approach involves direct substitution and differentiation rather than solving the entire equation.

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  • Familiarity with integrating factors in the context of first-order linear differential equations
  • Knowledge of differentiation techniques for higher-order derivatives
  • Ability to manipulate algebraic expressions involving functions and their derivatives
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  • Learn how to differentiate equations to find higher-order derivatives
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  • Practice solving initial value problems with varying conditions and equations
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mattbonner
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Homework Statement



Suppose that the initial value problem
y' = 7(x^2) + (5y^2) − 6, y(0)=−2
has a solution in an interval about x=0.

Find y'(0) =
Find y''(0) =
Find y'''(0) =

Homework Equations



get it into standard form: dy/dt + p(t)y = g(t)
find integrating factor = e^(\intp(t)dt + k

multiply everything by integrating factor, simplify left-hand-side and then integrate both sides

using initial condition, solve for C
solve for y

The Attempt at a Solution



i don't seem to be able to get it into standard form

i tried doing y' - 5y^2 = 7x^2 -6
which gave me an integrating factor of e^-5xy

i tried following the rest of the steps with that integrating factor but its not working
 
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You don't actually have to solve the equation to find the derivatives of y(x) at x=0. To find y'(0) just plug x=0, y=(-2) into the equation. To find the higher derivatives, just differentiate the equation with respect to x a couple of times.
 
oh wow i feel like such a moron
thank you so much!

edit: wait, for y''(0)

i differentiated it, and i got 14x?edit(2): nvm i solved it
 
Last edited:

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