Area Calculus

Optimization Calculus

Multiple Choice

A rectangle is bounded by the x-axis and the parabola  $$y=12-x^2$$ .  What length and width should the rectangle have so that its area is a maximum?  

Given the constraint equation above and the optimization equation  $$A=2xy$$  , choose the DERIVATIVE of the merged (combined) equation.

• $$A'=2xy$$  

• $$A'=\ \ 24-6x^2$$  

• $$A'=2x\left(12-x^2\right)$$  

• $$A'=12-2x$$  

Multiple Choice

A closed rectangular shipping box with square base is to be made from 120 square inches of cardboard. What dimensions should the box be for maximum volume?

Choose the constraint and optimization equations that represent the problem. 

• $$x^2=120$$  and  $$V=x^3$$  

• $$2x+y=120$$  and   $$V=xy$$  

• $$x^2y=120$$  and  $$V=2x^2+4xy$$  

• $$2x^2+4xy=120$$  and  $$V=x^2y$$  

Multiple Choice

A square piece of green origami paper that is 6 inches on a side is being made into a gift box (with no lid) by cutting congruent squares out of each corner, folding up the sides, and taping the edges.

What size squares should you cut out for maximum volume? (do the whole problem)

• I should cut out squares that are 1/2 in by 1/2 in

• I should cut out squares that are 1 in by 1 in

• I should cut out squares that are 3 in by 3 in

• I should not cut out any squares

Multiple Choice

Farmer Jo has 32 square feet of land in which to make an enclosure for bunnies, chicks, and penguins. (see picture)

Choose the equation that represents this information.

• $$2x+4y=32$$

• $$2x+2y=32$$

• $$xy=32$$

• $$A=3xy$$

Multiple Choice

You want to make a box to contain dirt and your pet earthworm. Using a 7 in by 10 in rectangle of cardboard, you cut congruent squares from the corners and fold up the sides.

Choose the equation would you use in order to do Calculus to find the maximum volume of dirt (including worm) the box can hold?

• $$V=\left(7-2x\right)\left(10-2x\right)$$

• $$V=x\left(7-2x\right)\left(10-2x\right)$$

• $$V=x\left(7-x\right)\left(10-x\right)$$

• $$V=x\left(7+2x\right)\left(10+2x\right)$$