Answer
$\dfrac{1}{1+i}=\dfrac{1}{2}-\dfrac{1}{2}i$
Work Step by Step
$\dfrac{1}{1+i}$
Multiply the fraction by $\dfrac{1-i}{1-i}$
$\Big(\dfrac{1}{1+i}\Big)\Big(\dfrac{1-i}{1-i}\Big)=\dfrac{1-i}{1-i^{2}}=...$
Since $i^{2}=-1$, the equation becomes:
$...=\dfrac{1-i}{1-(-1)}=\dfrac{1-i}{2}=\dfrac{1}{2}-\dfrac{1}{2}i$