a=3i^+2j^+2k^,b=i+2j^−2k^
∵α=a+b=4i^+4j^
β=a−b=2i^+4k^
∴α×β=∣i^42j^40k^04∣=i^(16)−j^(16)+k^(−8)=16i^−16j^−8k^
∴ Unit vector perpendicular to \vec{\alpha }& \vec{\beta } is
n^=∣α×β∣α×β=32i^−2j^−k^
∴ Required vector =123(2i^−2j^−k^)=4(2i^−2j^−k^)