At which value of x does f(x) = -x^2 + 8x attain its maximum?
फलन f(x) = -x^2 + 8x का maximum किस x पर होगा?
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Correct Answer
C. 4
ExplanationStep 1: The vertex of a downward quadratic gives the maximum. Step 2: f'(x) = -2x + 8; setting it zero gives x = 4. Step 3: For maximum or minimum, set the derivative equal to zero.
Step 1: Downward quadratic का vertex maximum देता है। Step 2: f'(x) = -2x + 8; zero रखने पर x = 4 मिलता है। Step 3: Maximum/minimum के लिए derivative zero करें।