[填空题]
In this question giv4:r1c bz1d:( t toarp4 qls,m*qn9 bmfe all x/goj(jge/ 5com)0 qz angles in radians.
Let $z=1+2 \mathrm{i}$ and $w=4+\mathrm{i}$ .
1. Find z+w . a+bi a = b =
2. Find:
1. $|z+w|$ ;≈
2. $\arg (z+w)$ .≈
3. Find $\theta $, the angle shown on the diagram below.≈
