Solution
= Solution
For the positive real base ten, use its real <natural logarithm>. Then <Euler's formula> gives
$$
\boxed{10^i=e^{i\ln10}=\cos(\ln10)+i\sin(\ln10).}
$$
= Solution
For the positive real base ten, use its real <natural logarithm>. Then <Euler's formula> gives
$$
\boxed{10^i=e^{i\ln10}=\cos(\ln10)+i\sin(\ln10).}
$$