Solution
= Solution
Multiply numerator and denominator by the <complex conjugate> of the denominator:
$$
\frac{1+i}{1-i}=\frac{(1+i)^2}{(1-i)(1+i)}=\frac{2i}{2}=\boxed{0+i}.
$$
The denominator is the squared <modulus> $|1-i|^2=2$.
= Solution
Multiply numerator and denominator by the <complex conjugate> of the denominator:
$$
\frac{1+i}{1-i}=\frac{(1+i)^2}{(1-i)(1+i)}=\frac{2i}{2}=\boxed{0+i}.
$$
The denominator is the squared <modulus> $|1-i|^2=2$.