Find the value of the second derivative when x = 20 for the following function: f(x) = 200x divided by (x+40)
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did you find the first derivative?
f(x) = 200x divided by (x+40) => f(x) = \frac{200x}{x+40} => f'(x) = \frac{200(x+40)-1*200x}{(x+40)^2} ... => f''(x) =
Last edited by Rapha; Nov 18th 2008 at 08:44 PM.
Originally Posted by Rapha f(x) = 200x divided by (x+40) => f(x) = \frac{200x}{x+40} => f'(x) = \frac{200(x+40)-1*200x}{(x+40)^2} ... => f''(x) = why didn't you simplify f'(x) ? $\displaystyle f'(x) = \frac{200(x+40)-1(200x)}{(x+40)^2}$ $\displaystyle f'(x) = \frac{200x + 8000 - 200x}{(x+40)^2}$ now finish the algebra clean-up for f'(x) and find f''(x).
Originally Posted by skeeter why didn't you simplify f'(x) ? i think it is his business, because simplify f'(x) is duck soup, isn't it?
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