Typo - Sine in terms of complex exponential
File in which the problem appears
src/1_complex_numbers.md
Also in the summary of the chapter.
Problematic sentence
Furthermore, we can define the sine and cosine in terms of complex exponentials:
\sin(x) = \frac{e^{{\rm i} x} - e^{-{\rm i} x}}{2}
Correct version
\sin(x) = \frac{e^{{\rm i} x} - e^{-{\rm i} x}}{2{\rm i}}
Edited by Dixit Sabharwal