The spelling of "pure imaginary number" is pronounced as /pjʊər ɪˈmædʒɪnəri ˈnʌmbə/. The 'p' in 'pure' is silent, while the first syllable is pronounced as 'pyu'. The 'i' in 'imaginary' is pronounced as 'ih' and there is a small glottal stop between the second syllable and the third syllable. The stress is on the second syllable in 'imaginary' and on the first syllable in 'number'. This phonetic spelling makes it easier to understand the pronunciation of the term.
A pure imaginary number is a complex number that can be written in the form ai, where a is a real number and i is the imaginary unit, defined as the square root of -1. In other words, it is a complex number that has no real part, only an imaginary part.
The term "pure" emphasizes the absence of any real component in the number. This means that a pure imaginary number lies on the imaginary axis of the complex plane. The imaginary axis is perpendicular to the real axis and consists of numbers of the form bi, where b is a real number and i is the imaginary unit.
Pure imaginary numbers are useful in mathematics, especially in the field of complex analysis. They play a fundamental role in describing the behavior of complex functions and solutions to certain differential equations. Additionally, they are commonly encountered when dealing with sinusoidal functions, such as those found in electrical engineering and physics.
It is important to note that pure imaginary numbers are distinct from real numbers and complex numbers with both real and imaginary parts. While real numbers lie on the real axis and complex numbers lie in the complex plane, pure imaginary numbers exist solely on the imaginary axis. They serve as an important element in the broader study of complex numbers and their applications.