Separation of Variables Solving First Order Differential Equations
Solving ODEs What is Solving an ODE? Eliminating All Derivatives Explicit Form Implicit Form
This Chapter 1st Order (Only First Derivative) Linear and Nonlinear
Calculus Brain Teaser: ?
Today We will try to make problems look like:
Why? Want to “Get Rid of” This Derivative
Why? So we integrate the left side Have to integrate right side too
Separation of Variables No more derivatives! Implicit (General) Solution
Separation of Variables No more derivatives! Implicit (Specific) Solution If we havecan solve for C
Chain Rule Remember, y is a function of t
Chain Rule
So To Solve Think of it as: (Reversing the Chain Rule)
So To Solve Think of it as: Find by solving Keep equation balanced by solving
The whole process… For an equation of the form: (May need to manipulate equation to get here)
The whole process… For an equation of the form: Separate the variables
The whole process… For an equation of the form: Separate the variables is
The whole process… For an equation of the form: Separate the variables Integrate both sides Perhaps solve for y, or C (if initial condition)
A Simple Example
A Convenient Technique
“Cross Multiply”
A Convenient Technique
Integral Curves Is solved by: or Equation for an ellipse (for different values of C)
Integral Curves Plots of Solutions for Different Values of -C are called “Integral Curves” Integral Curves Show Different Behaviors for Different Initial Conditions
Integral Curves
In Summary To Solve an ODE, eliminate derivatives One method for first order linear/nonlinear ODES Separation of Variables (Reverse Chain Rule) Integral curves are solution curves for different values of C
Questions?