Roots of Complex Numbers V8 Fall 2017
Let $n$ be a postive integer and let
$$Z = \big|Z\big|\big(cos(\theta) + sin(\theta)i\big)$$
be a complex number where $0 \lt \theta \le 2\pi.$ This app displays the
$n$-th roots of $Z$ which can be expressed as
$$R_{k} = \big|Z\big|^{\frac{1}{n}}\big[\cos\big(\frac{\theta+2\pi k}{n}\big) + \sin\big( \frac{\theta+2\pi k}{n} \big)i\big]$$
where $k = 0, 1, ..., n-1$. The root with the smallest positive angle will be called the basic primitive root
of $Z$.
From the formula above, it is the root
$$R_{0} = \big|Z\big|^{\frac{1}{n}}\big[cos\big(\frac{\theta}{n}\big) + sin\big(\frac{\theta}{n}\big)i\big]$$
and is displayed as a magenta vector. The remaining $n-1$ roots are displayed as cyan
vectors equally spaced around a yellow circle of radius $\big|Z\big|^{\frac{1}{n}}$ with
an angle of $\frac{2\pi}{n}$ separating one root from the next.
Instructions
- Enter $Z$ (drawn in green) by
- Selecting 0.5, 1, or 2 from the |Z| menu.
- Selecting 15, 30, 45, …, or 360 as its angle $\theta$ from the Z's Angle menu.
- Enter the roots to be found by selecting Square Roots, Cube Roots, …, or Sixth Roots from the Roots menu.
- Click the Start button.
Details:
- You can change the angle mode (degrees or radians) and the animation rate by using the Angle Mode, the Angle Curves and the Animation Rate menus, respectively.