# Complex Addition/Examples/Travel 2/Mistake

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## Source Work

1981: Murray R. Spiegel: *Theory and Problems of Complex Variables* (SI ed.)

- Chapter $1$: Complex Numbers
- Supplementary Problems: Polar Form of Complex Numbers: $85$

## Mistake

*An airplane travels $150 \, \mathrm {km}$ southeast, $100 \, \mathrm {km}$ due west, $225 \, \mathrm {km}$ $30 \degrees$ north of east, and then $323 \, \mathrm {km}$ northeast. Determine ... how far and in what direction it is from its starting point.*

*Ans. $\ 375 \, \mathrm {km}$, $23 \degrees$ north of east (approx.)*

## Correction

The correct solution is:

- $490$ kilometres in a direction $28.7 \degrees$ north of east from its starting point.

## Sources

- 1981: Murray R. Spiegel:
*Theory and Problems of Complex Variables*(SI ed.) ... (previous) ... (next): $1$: Complex Numbers: Supplementary Problems: Polar Form of Complex Numbers: $85 \ \text {(b)}$