Introduction to Complex Numbers

11. Roots, Radicals, and Complex Numbers / Introduction to Complex Numbers / Problem 1

Problem 1

Which expression is the definition of the imaginary unit $i$ ?

$i = \sqrt{- 1}$

$i equals 1$

$i = - \frac{1}{10}$

$i = - 1$

Which expression is the definition of the imaginary unit ii?