AoPS Wiki talk:Problem of the Day/July 11, 2011
Problem
AoPSWiki:Problem of the Day/July 11, 2011
Solution
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For the two graphs to be perpendicular, the slopes must be the negative reciprocals of one another. That is, the product of their slopes must be Rewriting the first line as we see that its slope is Thus, the slope of the second line must be Rewriting the equation of the second line, we have so its slope is Thus,