How do you simplify abs(19i )?

1 Answer
Dec 16, 2015

|19i| = 19

Explanation:

Given a complex number x+iy we have the complex modulus (the complex analog of an absolute value) defined to be
|x+iy| = sqrt(x^2 + y^2)

Thus

|19i| = |0+19i| = sqrt(0^2 + 19^2) = 19

Note that the complex modulus may also be viewed geometrically as the distance from a given point to the origin on the complex plane. Then, as 19i lies on one of the axes, we can immediately tell that the modulus of 19i will be the coefficient 19.