Three sides of a rectangular enclosure are to be made from closed board fencing costing $8.00 per metre and the fourth side is to be made from railings costing $4.50 per metre. The dimensions of the enclosure are not given but its area is 200m^2. Find the least (ie. minimum) cost of making the enclosure.

Question

anonymous · Answer

ahhhhh this isn't fun :(. is this algebra or calc. changes how you do the problem.

nottim · Answer

Well...calc makes it easier...

nottim · Answer

wat class/grade level/course?

anonymous · Answer

Calculus: Maxima and Minima.

anonymous · Answer

Grade 12 Maths Extension 2 from the book: Coroneos.

anonymous · Answer

And Maths Extension 2 is the highest level you can do for maths in Australian High Schools.

nottim · Answer

so den we using calc

anonymous · Answer

do you use algebra or calc. do you know what a derivative or lagrange multipler is?

anonymous · Answer

First derivative, second derivative.

nottim · Answer

dat it

nottim · Answer

?

anonymous · Answer

That it?. All you need is the first derivative and second derivative when solving this. BUt the hard part is forming an equation to differentiate.

hero · Answer

It's not that difficult. Find a formula for area and perimeter, then write one equation in terms of the other.

anonymous · Answer

Hah, I'm stuck on that. They don't give you dimensions. That's the hard part for me.

hero · Answer

Hang on bro

anonymous · Answer

Yep I have all that.

anonymous · Answer

I did everything like that. Nothing happened afterwards.

hero · Answer

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