E facts & stats

Question 1

Which letter is the most commonly used in written English?

Accepted Answer

E. Frequency counts of English text consistently show E as the most common letter.

Question 2

The mathematical constant e is approximately equal to what?

Accepted Answer

2.718. e is about 2.71828; 3.142 is π, 1.618 is the golden ratio and 1.414 is the square root of 2.

Question 3

The constant e is often called the number of which Swiss mathematician?

Accepted Answer

Leonhard Euler. Leonhard Euler used the letter e for the constant in the 1700s, and it's often called Euler's number.

Question 4

In calculus, what is the derivative of eˣ?

Accepted Answer

eˣ. eˣ is its own derivative: the function's slope at every point equals its value there.

Question 5

The SI prefix with the symbol 'E' stands for what?

Accepted Answer

Exa, meaning 10¹⁸. 'Exa' means 10¹⁸; for example, an exabyte is 10¹⁸ bytes.

Question 6

Which mathematician discovered the constant e in 1683 while studying compound interest?

Accepted Answer

Jacob Bernoulli. Jacob Bernoulli found that compounding more and more often approaches a limit, which we now call e.

Question 7

In 1873, Charles Hermite proved that e is what kind of number?

Accepted Answer

Transcendental. A transcendental number isn't the root of any polynomial with integer coefficients; Hermite proved this for e.

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