A rectangular block has a base which measures 2x x cm by 3x cm. Given that its volume is 1800cm^3 , prove that the total surface area, A cm^2, is given by A=12x^2 + 3000/x. Calculate the value of x for which A has a stationary value. Find this value of A and determine whether it is a maximum or a minimum. Ok, so I found out that x=900.Do I use the 1st or 2nd derivative test?
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Anonymous2007-12-21 1:22
OP here, I made a mistake-it's 2x cm by 3x cm.
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Anonymous2007-12-21 4:25
the 1st derivative test lets you discover in which values it MIGHT be maximum or minimum when you equals it to zero
on the 2nd you try the numbers you found in there
if its < 0 then its a maximum value, if its > 0, its a minimum.
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Anonymous2007-12-21 4:26
<3 calculus
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Anonymous2007-12-21 13:29
First is for maximums and minimums and second is for concavity