Calculate the position vector for 3di

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homeworkhelpls
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Homework Statement
Calculate the position vector for 3di
Relevant Equations
none
Numbered exercise 3 listing coordinate sets of points A, B and C in parts a to d, with sub-parts i and ii, including A(3, 8), B(-1, 2), C(51, 80) and A(a^2 + 2a, 3), B(a^2 + a - 1, 1), C(3a^2 + 2a - 2, 4a - 1).

for 3di i did the normal AB=BC so b-a would give either satisfy or not this phenomenon, my answer was (3a-1, -4) & (2a^2 + a - 1, 4a - 2), now how would i know from here if they're collinear or not?
 
homeworkhelpls said:
Homework Statement:: Calculate the position vector for 3di
Relevant Equations:: none

View attachment 315775
for 3di i did the normal AB=BC so b-a would give either satisfy or not this phenomenon, my answer was (3a-1, -4) & (2a^2 + a - 1, 4a - 2), now how would i know from here if they're collinear or not?
I don't know what you mean by "I did the normal AB = AC." The word "normal" usually means perpendicular.
Look at the slopes of the vectors AB, AC, and BC. I've already determined that the slopes of AB and AC are equal. If the slope of vector BC is equal to the other two slopes, then all three points are collinear -- i.e., lie on the same line.
 
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