2 What is Optimization Anyways? The term optimization means to optimize something, or use something at its best. This refers, both in real life and in Calculus, to the maximum or minimum value of something.When you optimize, you try to find the maximum or minimum value required for the given problemWhat is Optimization Anyways?
3 Equations You Should Know: Volume BOX:LWHHCONE:⅓πr²hWhrCYLINDER: πr²hrhSPHERE:¾πr³r
4 Equations You Should Know Area and Surface Area Circle:πr²Cylinder without top:πr²+2πrhwRectangle:2l+2wlCylinder with a closed top:2πr²+2πrh
5 Steps of OptimizationBEFORE YOU DO ANYTHING MAKE SURE YOU READ THE PROBLEM CAREFULLY!!!!1.DRAW THE PICTURE2.LABEL THE PICTURE WITH YOUR X’S AND Y’S3. WRITE OUT ANY EQUATIONS YOU WILL NEED3. SOLVE FOR EITHER Y OR X5. AFTER SOLVING FOR YOUR VARIABLE, PLUG THE SOLVED VARIABLE BACK INTO THE ORIGINAL EQUATION
6 Even More Steps 6. TAKE THE DERIVATIVE OF THAT EQUATION 7. SET THIS DERIVATIVE EQUAL TO ZERO8. SOLVE FOR EITHER Y OR X9. TAKE THE SECOND DERIVATIVE TO DETERMINE IF THIS IS THE MAX OR MIN10. PLUG THE SOLVED FOR VARIABLE BACK INTO THE EQUATION TO SOLVE FOR THE OTHER VARIABLE11.PLUG BOTH THE SOLVED VARIABLES BACK INTO THE EQUATION TO GET THE FINAL ANSWER
7 Lets Try This Out!A shepherd wishes to build a rectangular fenced area against the side of a barn. He has 360 feet of fencing material, and only needs to use it on three sides of the enclosure, since the wall of the barn will provide the last side. What dimensions should the shepherd choose to maximize the area of the enclosure?
9 Use the needed equations to solve for either x or y We know that the perimeter has to be 360 feet so we can plug this into the perimeter equationP= 360360= 2y+xSince we are dealing with area and perimeter we only need 2 equations:A= xyP= 2y+xIn this case, we will solve for x360= 2y+xX= 360-2y
10 Plug it back in and get the derivative Now that we have solved for x, we can plug this into the other equation to solve for our other variableA= xyX= 360-2yA=(360-2y)yA= 360y-2y²Now that we have our equation, take the derivativeA= 360y-2y²A’=360-2y
11 SET THE DERIVATIVE EQUAL TO ZERO A’= 360-4y 4(90-y) = 0 y = 90 ft Now that we have our y value, we can plug this back into the original equation to get our answer!360= 2y+xY= 90360= 2(90)+xSo to get the maximum are of the fence, y should be 90 ft and x should be 180 ft.360=180+xX= 180
12 Take the derivative again Once you find your value to plug in, take the second derivative to find if what you have is a relative maximum or minimumA’= 360-4yA’’= -4if A’’<0 then the value is a relative maxIf A’’>0 then the value is a relative min-4<0Therefore this is a relative max
13 Problem #1An open rectangular box with square base is to be made from 48 ft.2 of material. What dimensions will result in a box with the largest possible volume ?
14 Let’s See How We Did!DRAW IT OUT!!!SA: X²+4XYV: X²Yyxx
19 Problem #3A piece of sheet metal is rectangular, 5ft wide and 8ft long. Congruent squares are to be cut from its corners. The resulting piece of metal is to be folded and welded to form an open top box. How should this be done to get a box of largest possible volume?
20 Let’s See How We Did!DRAW IT OUT!!!88-2x55-2xxxx5-2x8-2x
21 V=lwhV= x(8-2x)(5-2x)(8x-2x²)(5-2x)4x³-26x²-40xV’=12x²-52x-404(3x²-13x-10)4(3x-10)(x-1)X= 1, 10/3X≠ 10/3X= 15-2(1)= 38-2(1)= 6The cut outs will be 1 in on each side and the lengths of the box will be 6x3x16113136
22 Now It’s Your Turn!Find the maximum volume of a right cylinder that can be inscribed in a cone of altitude 12 inches and a base radius 4 inches if the axes of the cylinder and cone coincide
24 Here, Try Another OneA rectangular plot of land containing 216 square meters is to be enclosed by a fence and divided into two equal parts by another fence parallel to one of the sides. What dimensions of the outer rectangle require the smallest total length for the two fences?
28 If You Want Even More Practice TRY THESE PROBLEMS! A window is in the shape of a rectangle surmounted by a semicircle. Find the dimensions when the perimeter is 24 meters and the area is as large as possibleA container with a rectangular base, rectangular sides, and no top is to have a volume of 2 cubic meters. The width of the base is to be 1 meter. When cut to size, material costs $10 per square meter for the base and $5 per square meter for the sides. What is the cost of the least expensive container?A circular cylindrical container, open at the top and having a capacity of 24π cubic inches, is to be manufactured. If the cost of the material used for the bottom of the container is three times that used for the curved part and there is no waste of material, find the dimensions which will minimize the cost.
29 Getting Ready For The AP Exam 1979 AB3 BC3Find the maximum volume of a box that can be made by cutting out squares from the corners of an 8 inch by 15 inch rectangular sheet of cardboard and folding up the sides.
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