Answer
$i^{10}=-1$
Work Step by Step
$i^{10}=(i^{2})^{5}$ and $i^{2}=\sqrt -1\times\sqrt -1=-1$ hence $i^{10}=(-1)^{5}$.
$(-1)^{5}=-1\times-1\times-1\times-1\times-1=-1$.
Hence the asnwer written in the form $a+bi$ where $a$ represents the real part and $b$ represents the imaginary part is $-1$ because $a=-1$ and $b=0$ as there is no imaginary part.