For $x=\pi,$, the value of the complex exponential function $\exp(ix)=-1.$ Therefore, the following result holds:
\[e^{i\pi}+1=0\]
This result is known as Euler's identity. It is remarkable since it unifies $4$ important numbers in only one equation: * the real number zero $0,$ * the real number one $1,$ * the $\pi$ constant, and * the imaginary unit $i.$
Proofs: 1
Corollaries: 1
