Help with c) please. My answer for b is (3,-2) and (18,8). Thank you?
回答 (1)
2015-09-20 9:30 am
✔ 最佳答案
A = ( 2 , 0 ) , P = ( 3 , -2 ) , Q = ( 18 , 8 )So, vector AP = ( 1, -2 ) , vector AQ = ( 16 , 8 )
AP．AQ = 1*16 + (-2)*8 = 0 , where ．denotes dot product
Hence, ∠PAQ = 90°
Q.E.D.
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