Imaginary unit
The imaginary unit, , is the fundamental component of all complex numbers. In fact, it is a complex number itself. It has a magnitude of 1, and can be written as .
Problems
Introductory
- Find the sum of
Solutions
Introductory
- Let's begin by computing powers of .
- We can now stop because we have come back to our original term. This means that the sequence i, -1, -i, 1 repeats. Note that this sums to 0. That means that all sequences have a sum of zero (k is a natural number). Since , the original series sums to the first two terms of the powers of i, which equals .