Depending on the additional context (if any is given), the answer is likely "gold and ivory."
The mathematical concepts that Leonhard Euler's legacy included are as follows:
The formalization of function notation
The notation for the imaginary unit
The notation for the base of the natural logarithm
Remember, that all of Euler's legacy included the introduction of the concept of functions as well as the proper way to write them within a mathematical formula by using the notation f(x). Before his formalization of the notation, functional relationships were referred to by just one letter, F, or with Greek letters omitting the parentheses, φx. In fact, Euler spelled out much of the mathematical notation we use today, including the letter "e" for the base of the natural logarithm (also known as Euler's number), the letter "I" to denote the imaginary unit, and the Greek letter "Σ" for summations. He also encouraged the use of the Greek letter "π" to signify the ratio of a circle's circumference to its diameter.
<span>Lyric poetry was first composed in ancient Greece using the lyre.
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