Perplex
Dashboard
Browse by TopicReview VideosFormula BookletMy Progress
BlogLanding Page
Sign UpLogin
Perplex
Perplex
Dashboard
Browse by TopicReview VideosFormula BookletMy Progress
BlogLanding Page
Sign UpLogin
Perplex
IB Math AAHL
/
Differential Equations
/
Skills
Edit

Skill Checklist

Track your progress across all skills in your objective. Mark your confidence level and identify areas to focus on.

Track your progress:

Don't know

Working on it

Confident

📖 = included in formula booklet • 🚫 = not in formula booklet

Track your progress:

Don't know

Working on it

Confident

📖 = included in formula booklet • 🚫 = not in formula booklet

IB Math AAHL
/
Differential Equations
/
Skills
Edit

Skill Checklist

Track your progress across all skills in your objective. Mark your confidence level and identify areas to focus on.

Track your progress:

Don't know

Working on it

Confident

📖 = included in formula booklet • 🚫 = not in formula booklet

Track your progress:

Don't know

Working on it

Confident

📖 = included in formula booklet • 🚫 = not in formula booklet

Skill Checklist

Track your progress across all skills in your objective. Mark your confidence level and identify areas to focus on.

6 Skills Available

Track your progress:

Don't know

Working on it

Confident

📖 = included in formula booklet • 🚫 = not in formula booklet

Track your progress:

Don't know

Working on it

Confident

📖 = included in formula booklet • 🚫 = not in formula booklet

Solving Differential Equations

5 skills
Separable Variables
AHL 5.18

When you have a differential equation in the form

​
dxdy​=f(x)g(y)🚫
​

you can bring all the ​y​'s to one side and all the ​x​'s to the other:

​
g(y)1​dy=f(x)dx🚫
​
​
∫g(y)1​dy=∫f(x)dx🚫
​


Particular Solutions
AHL 5.18

The solutions to differential equations will usually contain a constant of integration ​+C. These are called general solutions.


Often, we are given an initial condition, ie the value of ​y​ for a specific ​x, which we can use to solve for ​C. The result is the particular solution.

Direct Integration
AHL 5.18

The easiest differential equations to solve are the ones in the form

​
dxdy​=f(x)
​

as we can simply integrate:

​
y=∫f(x)dx🚫
​
Integrating Factor
AHL 5.18

For a differential equation in the form

​
dxdy​+P(x)y=Q(x)
​

Multiply both sides by integrating factor (often called ​μ​):

​
e∫P(x)dx📖
​

and notice the product rule on the LHS.

Homogeneous Equation
AHL 5.18
​
dxdy​=f(xy​)🚫
​


Let ​y=vx, then ​v=xy​.


Note: On IB exams you will be told to use the substitution ​y=vx.

Euler's Method

1 skill
Performing Euler's Method
AHL 5.18

Mathematically Euler's Method works as follows:

  1. Start at a known point ​(x0​,y0​)​

  2. Pick a step size ​h​ such that ​x0​+nh=xfinal​​ for some integer ​n.

Repeat the following steps for each ​n​ until the desired ​x​-value is reached:

  1. Find the slope ​dxdy​=f(xn​,yn​)​

  2. Find the next ​x​ value ​xn+1​=xn​+h📖.

  3. Find the next ​y​-value ​yn+1​=yn​+h×f(xn​,yn​)📖​

Skill Checklist

Track your progress across all skills in your objective. Mark your confidence level and identify areas to focus on.

6 Skills Available

Track your progress:

Don't know

Working on it

Confident

📖 = included in formula booklet • 🚫 = not in formula booklet

Track your progress:

Don't know

Working on it

Confident

📖 = included in formula booklet • 🚫 = not in formula booklet

Solving Differential Equations

5 skills
Separable Variables
AHL 5.18

When you have a differential equation in the form

​
dxdy​=f(x)g(y)🚫
​

you can bring all the ​y​'s to one side and all the ​x​'s to the other:

​
g(y)1​dy=f(x)dx🚫
​
​
∫g(y)1​dy=∫f(x)dx🚫
​


Particular Solutions
AHL 5.18

The solutions to differential equations will usually contain a constant of integration ​+C. These are called general solutions.


Often, we are given an initial condition, ie the value of ​y​ for a specific ​x, which we can use to solve for ​C. The result is the particular solution.

Direct Integration
AHL 5.18

The easiest differential equations to solve are the ones in the form

​
dxdy​=f(x)
​

as we can simply integrate:

​
y=∫f(x)dx🚫
​
Integrating Factor
AHL 5.18

For a differential equation in the form

​
dxdy​+P(x)y=Q(x)
​

Multiply both sides by integrating factor (often called ​μ​):

​
e∫P(x)dx📖
​

and notice the product rule on the LHS.

Homogeneous Equation
AHL 5.18
​
dxdy​=f(xy​)🚫
​


Let ​y=vx, then ​v=xy​.


Note: On IB exams you will be told to use the substitution ​y=vx.

Euler's Method

1 skill
Performing Euler's Method
AHL 5.18

Mathematically Euler's Method works as follows:

  1. Start at a known point ​(x0​,y0​)​

  2. Pick a step size ​h​ such that ​x0​+nh=xfinal​​ for some integer ​n.

Repeat the following steps for each ​n​ until the desired ​x​-value is reached:

  1. Find the slope ​dxdy​=f(xn​,yn​)​

  2. Find the next ​x​ value ​xn+1​=xn​+h📖.

  3. Find the next ​y​-value ​yn+1​=yn​+h×f(xn​,yn​)📖​