 <p>e to the power of something imaginary can be computed with sin and cos waves<br> <img src="https://i.stack.imgur.com/uqQ3i.png" alt="http://upload.wikimedia.org/math/4/0/d/40d9a3c31c4a52cb551dd4470b602d82.png"><br> <a href="http://en.wikipedia.org/wiki/E_(mathematical_constant)" rel="nofollow noreferrer">wikipedia entry for e</a></p> <p>and vector exponentiation has it's own page as well<br> <img src="https://i.stack.imgur.com/MAW0W.png" alt="alt text"><br> <a href="http://en.wikipedia.org/wiki/Matrix_exponential" rel="nofollow noreferrer">matrix exponential</a></p>