Rate of Change


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An equation that defines rate of change is called an differential equation. You need to know how to formulate one from information given in a question.

Example 1:

Example 1
Answer 1
Example 2
Answer 2

Note: In a question like this, you need to define any additional variables not given in the question that you are using in your equation, unless stated otherwise. This is so that the examiner knows what you have understood from the context.

It is very important to understand the context, as for harder problems, you would need to use the chain rule, combining different variables and equations together.

Example 2:

Example 1
Answer 1
Example 2
Answer 2

Practice Question:





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Note: Usually forming these differential equations are combined with a part that solves them. Solving differential equations is covered in the Integration part of the course.