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#1 2007-11-17 05:33:18
- Identity
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- Registered: 2007-04-18
- Posts: 934
applications of differentiation
The gradient graph of the cubic function with rule y = f(x) crosses the x-axis at (1,0) and (-2,0). The maximum value of the gradient function is 6. What is the value of x for which the graph of y = f(x) has a local minimum?
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#2 2007-11-17 06:45:28
- JaneFairfax
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- Registered: 2007-02-23
- Posts: 6,868
Re: applications of differentiation
The gradient graph is a quadratic curve. The fact that it has a maximum (rather than minimum) says that the coefficient of x[sup]3[/sup] in f(x) is negative. Hence f(x) attains its local minimum before it attains its local maximum. So the answer is to the question is x = −2.
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