3#
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小 發表於 2017-3-17 03:00 AM (第 2569 天)
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yes A is definitely (-1,5) , I copied the wrong coordinates from my rough working! Just from the diagram, (-2,2) is an impossible answer!
Q is (3,-3) so P is (-3,3) due to symmetry so OP is 135 deg to x-axis & as PA is right angled to OP so PA is 45 deg to x-axis and as PA=a=2sqrt2 so A is acos45 to right of P and also asin45 above P i.e. 2 units to the right and 2 units above P so A is (-3+2, 3+2) = (-1,5)