High school mathematics vector inequality synthesis Given the vector a = (y, x + 5), B = (y, x + 5), x > 0, Y > 0, and a is perpendicular to B, what is the minimum value of XY Change a = (4-x, 1)
Problem, a and B are equal, how can vector be vertical
In that case, it's 0
(4-x)y+(x+5)=0
x(y-1)=9
So the minimum XY is 0
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