Question 118344: please help me to solve this problem: Given the points P(-1,-2) Q(4,2) and R(1,m) in the coordinate plane. find the value of m so that PR + PQ is minimum.
thanks!!!
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Given the points P(-1,-2) Q(4,2) and R(1,m) in the coordinate plane. find the value of m so that PR + PQ is minimum.
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PR = sqrt[(m+2)^2+(1+1)^2] = sqrt[m^2+2m+5]
PQ = sqrt[(2+2)^2+(4+1)^2] = sqrt[41]
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PR + PQ = sqrt[m^2+2m+5] + sqrt[41]
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To minimize the sum we need to minimize m^2+2m+5:
That occurs when m = -b/2a = -2/2 = -1
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Cheers,
Stan H.
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