Two positive numbers have sum . What is the least possible value of the sum of their squares?
Answer and explanation
Correct answer: D.
- Step 1: Let the numbers be and ; . Step 2. gives , and so it is a minimum. Step 3. . **Answer: . Why not the others:** : This is only , one of the two squares. : This is , which is the value when one number is (an endpoint, not the minimum). : This is not attained at the critical point or at an endpoint.
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