Find the maximum rate of increase of the function y = -x^3 + 6x^2 - 5x + 3.

Answer and explanation

Correct answer: C. 7

  1. Step 1: Rate of increase is the derivative: y' = -3x^2 + 12x - 5. Step 2. To maximize y', find where its derivative is zero: y'' = -6x + 12 = 0 => x = 2. Step 3. Since y''' = -6 < 0, x = 2 gives the maximum of y'. Step 4. Evaluate y' at x = 2: y'(2) = -3(4) + 12(2) - 5 = -12 + 24 - 5 = 7. Answer: 7. Why not the others: 5 is the constant in y'; 6 is the coefficient of x^2; 8 is an addition slip.

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