How to Put E on Graphing Calculator
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Reviewed by Calculator Editorial Team
Euler's number (e) is a fundamental mathematical constant approximately equal to 2.71828. It appears in many areas of mathematics, including calculus, exponential growth, and probability. This guide explains how to input and use e on various graphing calculators.
What is E in Math?
Euler's number, denoted as e, is a mathematical constant approximately equal to 2.718281828459045. It's the base of the natural logarithm and has unique properties in calculus and exponential functions.
The value of e is defined by the infinite series:
e = 1 + 1/1! + 1/2! + 1/3! + 1/4! + ...
In many scientific and engineering applications, e is used to model growth and decay processes, such as population growth, radioactive decay, and compound interest.
How to Input E on Different Calculators
TI-84 Series
- Press the [2ND] key
- Press the [e^x] key (this will display "e")
- To use e in an equation, enter it as "e" or "e^x" depending on your needs
Casio fx-CG50
- Press the [SHIFT] key
- Press the [e^x] key (this will display "e")
- Use "e" in your equations as needed
HP Prime
- Press the [e] key (located on the main keyboard)
- To use e in calculations, simply enter "e" in your expression
General Tips
- Always check your calculator's manual for the exact key combination
- Some calculators may require you to press [2ND] or [SHIFT] before accessing e
- Remember that e is case-sensitive on most calculators
Using E in Equations
Once you've entered e on your calculator, you can use it in various mathematical expressions:
Exponential Functions
To calculate e raised to a power (e^x):
e^x = e * e * e * ... (x times)
Natural Logarithm
The natural logarithm (ln) is the inverse of the exponential function with base e:
ln(e) = 1
ln(e^x) = x
Example Calculation
Let's calculate e^2 (e squared):
- Input "e" on your calculator
- Press the [^] key (exponentiation)
- Enter "2"
- Press [=] to get approximately 7.389
Common Mistakes
Remember that e is not the same as the number 2.718. It's a mathematical constant with infinite non-repeating digits.
- Confusing e with π (pi) - they are different constants
- Forgetting to press [2ND] or [SHIFT] before accessing e on some calculators
- Assuming e is an integer when it's actually an irrational number
- Using e in place of 10 in decimal calculations
FAQ
- How do I input e on my TI-84 calculator?
- Press [2ND] then [e^x] to access the e constant.
- Is e the same as 2.718?
- No, e is approximately 2.718 but has infinite non-repeating digits.
- Can I use e in graphing functions?
- Yes, input "e" in your Y= equation to use it in graphing.
- What's the difference between e and π?
- e is approximately 2.718 while π is approximately 3.1416. They serve different mathematical purposes.
- How do I calculate e^x on my calculator?
- Enter "e" then press [^] and enter your exponent value.
About this calculator
Updated June 25, 2026. Formulas, assumptions, and limitations are shown directly on this page.
Formula and Sources
The value of e is defined by the infinite series: e = 1 + 1/1! + 1/2! + 1/3! + ...
For more information about Euler's number, visit the Wikipedia page on e.