Euler

Which of these is not a problem or theory Euler tried to solve or make?

Which of these symbols did Euler not make or popularize?

What was Euler originally supposed to be?

What was the name of Euler's first book?

What mathematician(s) were the reason Euler went to Russia to become a mathematician?

When was Euler born?

Which of these is not used in trigonometry and not made by Euler?

Which of these did Euler not make/popularize?

Which of these is not an irrational number made/popularized by Euler?

Which of these was made by Euler?