Posted by Steve on November 13, 2002 at 12:40:32:
In Reply to: Max/Min problems posted by Nikos Zavoulodis on November 05, 2002 at 21:16:17:
Sounds like you may not understand why derivatives are taught before max/min. The max/min occurs where the derivative (which can be used to get the slope of at any point of the function) is zero.
For example: F(x)= -5x^2 - 7
Then F'(x) = -10x
So the min/max occurs when: -10x = 0; which means min/max occurs when x=0; the y value associated with x=0 is y = -7; so min/max is at the point (0,-7)
To determine if the point of the function is a min/max you need to determine whether it is concave up or concave down at that point. Concavity is determined by using the second derivative.
Hope this helps. If you have other question, feel free to email me.
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