# Appendix G - Complex Numbers - G Exercises - Page A56: 44

$-1$

#### Work Step by Step

To write the number as $a+bi$, we apply Euler's formula, $e^{iy}=\cos{y}+i\sin{y}$ $e^{-i\pi}=\cos(-\pi)+i\sin(-\pi)=-1+i*0=-1$

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