A) the vector a+b
B) a unit vector parallel to a+b
C) a unit vector perpendicular to both a and b
ans:A)-2i-3j+3k
B)1/((22)^(1/2))*(-2i-3j+3k)
C)+ and - 1/((341)^(1/2))*(9i+8j+14k)
P.S. X^(1/2) means 開方x
更新1:
ANDREW: 可唔可以詳細解釋下點解part c 係a*b? 我唔係好明part c講咩同你個working out~.~" thank you very much~
更新2:
仲有, 你最後的+ and - 係點黎嫁