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Multiple Choice
Let . For what value of does have a critical point at ?
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Verified step by step guidance
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To find the critical points of the function f(x) = x^3 + a x^2, we first compute its derivative f'(x). The derivative of x^3 is 3x^2, and the derivative of a x^2 is 2a x. Thus, f'(x) = 3x^2 + 2a x.
Critical points occur where the derivative f'(x) equals 0. Set f'(x) = 0: 3x^2 + 2a x = 0.
Factor the equation 3x^2 + 2a x = 0. This gives x(3x + 2a) = 0. The solutions to this equation are x = 0 or 3x + 2a = 0.
We are given that there is a critical point at x = 1. Substitute x = 1 into the equation 3x + 2a = 0 to find the value of a. This gives 3(1) + 2a = 0.
Solve the equation 3 + 2a = 0 for a. Subtract 3 from both sides to get 2a = -3, and then divide by 2 to find a = -3.