SOLUTION: Find the point on the graph of the function that is closest to the given point. f(x) = sqrt(x − 7) , (19, 0)

Algebra ->  Coordinate Systems and Linear Equations -> SOLUTION: Find the point on the graph of the function that is closest to the given point. f(x) = sqrt(x − 7) , (19, 0)      Log On


   



Question 1125369: Find the point on the graph of the function that is closest to the given point.
f(x) = sqrt(x − 7) , (19, 0)

Answer by greenestamps(13198) About Me  (Show Source):
You can put this solution on YOUR website!


A point on the graph of the function has coordinates (x,sqrt(x-7)).

To minimize the distance between that point and (19,0), we can minimize the square of the distance.

The square of the distance between (x,sqrt(x-7)) and (19,0) is

%28x-7%29%2B%28x-19%29%5E2+=+x-7%2Bx%5E2-38x%2B361+=+x%5E2-37x%2B361

The minimum value of a quadratic function ax^2+bx+c is when x = -b/2a.

The value of x that gives the minimum distance between (x,sqrt(x-7)) and (19,0) is -(-37/2) = 37/2.

The point on the graph closest to (19,0) is (37/2,f(37/2)) = (37/2,sqrt(23/2)).