SOLUTION: The difference of two numbers is 1. What is the smallest possible value for the sum of their squares? Find the numbers.

Algebra ->  Customizable Word Problem Solvers  -> Numbers -> SOLUTION: The difference of two numbers is 1. What is the smallest possible value for the sum of their squares? Find the numbers.      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


   



Question 437040: The difference of two numbers is 1. What is the smallest possible value for the sum of their squares? Find the numbers.
Answer by oberobic(2304) About Me  (Show Source):
You can put this solution on YOUR website!
x = one number
y = a number that is one less than x
y = x-1
.
The sum of squares =
x%5E2+%2B+%28x-1%29%5E2+=+x%5E2+%2B+x%5E2+-2x+%2B+1
x%5E2+%2B+x%5E2+-2x+%2B+1+=+2x%5E2+-2x+%2B+1
.
Assuming you mean 'integers' when you say 'numbers', then we could try some values:
When x = 0, the sum of squares = 1
When x = -1, the sum of squares = 4
When x = 1, the sum of squares = 1
...
But randomly plugging in values of x and checking the sum is not a very mathematical approach.
Instead, let's look at the graph:
graph%28500%2C500%2C-10%2C10%2C-10%2C10%2C2%2Ax%2Ax+-+2%2Ax+%2B+1%29
We immediately see this is a parabola and that the minimum value occurs when x = 1/2.
Checking this value we find:
2x%5E2+-2x+%2B+1+=+2%281%2F4%29+-2%281%2F2%29+%2B+1
2%281%2F4%29+-2%281%2F2%29+%2B+1+=+1%2F2+-1+%2B+1
1%2F2+-1+%2B+1+=+1%2F2
Looking back at the question it asks for two numbers
x+=+1%2F2
x-1+=+-1%2F2
What is their sum of their squares?
1%2F4+%2B+1%2F4+=+1%2F2
That fits with our graph, too.
Answer: The two numbers are 1/2 and -1/2.
Done.