Exercises 12.4, page 356

1. $5 (\cos 126.9 ° + j \sin 126.9 °)$ $5 (\cos 126.9 ° + j \sin 126.9 °)$
3. $10 (\cos 36.9 ° + j \sin 36.9 °)$ $10 (\cos 36.9 ° + j \sin 36.9 °)$
5. $50 (\cos 306.9 ° + j \sin 306.9 °)$ $50 (\cos 306.9 ° + j \sin 306.9 °)$
7. $3.61 (\cos 123.7 ° + j \sin 123.7 °)$ $3.61 (\cos 123.7 ° + j \sin 123.7 °)$
9. $0.60 (\cos 204 ° + j \sin 204 °)$ $0.60 (\cos 204 ° + j \sin 204 °)$
11. $2 (\cos 60 ° + j \sin 60 °)$ $2 (\cos 60 ° + j \sin 60 °)$
13. $8.062 (\cos 295.84 ° + j \sin 295.84 °)$ $8.062 (\cos 295.84 ° + j \sin 295.84 °)$
15. $3 (\cos 180 ° + j \sin 180 °)$ $3 (\cos 180 ° + j \sin 180 °)$
17. $9 (\cos 90 ° + j \sin 90 °)$ $9 (\cos 90 ° + j \sin 90 °)$
19. $2.94 + 4.05 j$ $2.94 + 4.05 j$
21. $- 139 + 80.0 j$ $- 139 + 80.0 j$
23. $- 1.85 - 2.36 j$ $- 1.85 - 2.36 j$
25. 0.08
27. $- 120 j$ $- 120 j$
29. $- 4.71 + 0.595 j$ $- 4.71 + 0.595 j$
31. $- 0.6052 - 0.7096 j$ $- 0.6052 - 0.7096 j$
33. 7.32j
35. $- 6.961 + 86.14 j$ $- 6.961 + 86.14 j$
37. $180 °$ $180 °$
39.

$\begin{array}{lcl} conj . of r (\cos θ + j \sin θ) & = & r (\cos θ - j \sin θ) \\ = & r (\cos (- θ) + j \sin (- θ)) \\ = & r ∠ \underline{- θ} \end{array}$ $\begin{array}{lcl} conj . of r (\cos θ + j \sin θ) & = & r (\cos θ - j \sin θ) \\ = & r (\cos (- θ) + j \sin (- θ)) \\ = & r ∠ \underline{- θ} \end{array}$
41. $3.03 ∠ \underline{339.5} ° kV$ $3.03 ∠ \underline{339.5} ° kV$
43. $2.51 + 12.1 j V/m$ $2.51 + 12.1 j V/m$