The sum of two numbers is 16. The sum of their squares is a minimum. Determine the number
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OpenStudy (anonymous):
WHAT DOES THIS MEAN D:
OpenStudy (aum):
Let the two numbers be: x and (16-x)
You need to minimize x^2 + (16-x)^2
OpenStudy (aum):
x^2 + (16-x)^2 is a vertical parabola that opens upward. Minimum will be at the vertex.
OpenStudy (anonymous):
8,8
OpenStudy (anonymous):
its saying the sum of 2 numbers which is x and y so the equation can be like
x + y = 16 or y = -x + 16
the sum of two squares can be written as
x^2 + y^2 because of the first equation
then x^2 + (-x + 16)^2 = x^2 + (-x +16)(-x + 16)
then expand the binomial
you will get x^2 + x^2 - 16x - 16x + 256
2x^2 - 32x + 256
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OpenStudy (anonymous):
x^2 + (16-x)^2
=2x^2 -32x +196
=2(x-8)^2 +132
so min when x=8
OpenStudy (anonymous):
there are 2 ways to find the minimum for that function -b/2a
-32/4 = 8
OpenStudy (anonymous):
x^2 + (16-x)^2 =2x^2 -32x +256 (error in calculation)
=2(x-8)^2 +192
so min when x=8
OpenStudy (anonymous):
min is 8
OpenStudy (anonymous):
thanks guys! i appreciate your help :D
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