Derivatives of Exponential Functions (Edexcel AS Maths): Revision Note
Did this video help you?
Derivatives of Exponential Functions
What is the derivative of e?
y = ex has the particular property
ie for every real number x, the gradient of y = ex is also equal to ex (see Derivatives of Exponential Functions)
![Derivatives of Exponential Functions Notes fig1, A Level & AS Maths: Pure revision notes](https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=3840/https://cdn.savemyexams.com/uploads/2020/07/6.1.4-Derivatives-of-Exponential-Functions-Notes-fig1.png)
![Derivatives of Exponential Functions Notes fig2, A Level & AS Maths: Pure revision notes](https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=3840/https://cdn.savemyexams.com/uploads/2020/07/6.1.4-Derivatives-of-Exponential-Functions-Notes-fig2.png)
e ≈ 2.718 (see "e")
Recall that the derivative is the gradient function for a curve (see First Principles Differentiation)
Graphs and derivatives related to e
![Derivatives of Exponential Functions Notes fig3, A Level & AS Maths: Pure revision notes](https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=3840/https://cdn.savemyexams.com/uploads/2020/07/6.1.4-Derivatives-of-Exponential-Functions-Notes-fig3.png)
The derivative of y = ekx is
The derivative of y = e-kx is
Examiner Tips and Tricks
Remember that (like π) e is a number.
Exam questions can ask for answers to be given as exact values in terms of e (see the Worked Example below).
Worked Example
![Derivatives of Exponential Functions Example fig1, A Level & AS Maths: Pure revision notes](https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=3840/https://cdn.savemyexams.com/uploads/2020/07/6.1.4-Derivatives-of-Exponential-Functions-Example-fig1.png)
![Derivatives of Exponential Functions Example fig2, A Level & AS Maths: Pure revision notes](https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=3840/https://cdn.savemyexams.com/uploads/2020/07/6.1.4-Derivatives-of-Exponential-Functions-Example-fig2.png)
![Derivatives of Exponential Functions Example fig3, A Level & AS Maths: Pure revision notes](https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=3840/https://cdn.savemyexams.com/uploads/2020/07/6.1.4-Derivatives-of-Exponential-Functions-Example-fig3.png)
![Derivatives of Exponential Functions Example fig4, A Level & AS Maths: Pure revision notes](https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=3840/https://cdn.savemyexams.com/uploads/2020/07/6.1.4-Derivatives-of-Exponential-Functions-Example-fig4.png)
![Derivatives of Exponential Functions Example fig5, A Level & AS Maths: Pure revision notes](https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=3840/https://cdn.savemyexams.com/uploads/2020/07/6.1.4-Derivatives-of-Exponential-Functions-Example-fig5.png)
You've read 0 of your 5 free revision notes this week
Sign up now. It’s free!
Did this page help you?