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1. Anyone who can help?

C2 differentiation: Stationary points question

5. the diagram above shows an open-topped water tank in the shape of a cuboid, which is made of sheet metal. the base of the tank is a rectangle x metres by y metres. the height of the tank is x metres
The capacity of the tank is 100m3
a) show that the A m2 of the sheet metal used to make the tank is given by A=300/x +2x(squared)

b)use calculus to find the value of x for which A is stationary
c)Prove that this value of x gives a minimum value of A
d) calculate the minimum area of sheet metal to make the tank

any solutions roughly worked out A so mainly just B, C and D
2. (Original post by Saraht31)
Anyone who can help?

C2 differentiation: Stationary points question

5. the diagram above shows an open-topped water tank in the shape of a cuboid, which is made of sheet metal. the base of the tank is a rectangle x metres by y metres. the height of the tank is x metres
The capacity of the tank is 100m3
a) show that the A m2 of the sheet metal used to make the tank is given by A=300/x +2x(squared)

b)use calculus to find the value of x for which A is stationary
c)Prove that this value of x gives a minimum value of A
d) calculate the minimum area of sheet metal to make the tank

any solutions roughly worked out A so mainly just B, C and D
What have you tried for B?
3. (Original post by SeanFM)
What have you tried for B?
I don't know how to explain it, but it's a long twisted way that isn't correct in any shape or form
4. (Original post by Saraht31)
I don't know how to explain it, but it's a long twisted way that isn't correct in any shape or form
Ok, no worries.

From part a you have that A=300/x +2x(squared)

and part b is asking for value of x for which A is stationary... so what does your instinct tell you?

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