I got 6.3 not sure if Im right
You have to make a cos graph that starts its minimum and of -2, has an amplitude of 10, a period of 10 and a maximum of 18.
I decided to use a cos graph since cos graphs start at their minimum or maximum unlike a sine graph that starts halfway between the minimum and maximum. You also know the amplitude has to be 10 since 18+2=20 and 20/2=10. We were also told that the water wheel completels a rotation every 10 minutes which means the period is 10 minutes.
lets start of with a regular cos(x) graph. This starts on its maximum instead of minimum so we have to multiply it by -1 to get -cos(x) which does start on its minimum.
-cos(x) has an amplitude of 1 instead of 10, to fix that we multiply it by 10 to get -10cos(x) which has an amplitude of 10.
-10cos(x) has a period of 2π instead of 10, to fix this we multiply the x by 2π/10 to get -10cos((π/5)x) which now has a period of 10.
-10cos((π/5)x) has a minimum of -10 and maximum of 10 instead of a minimum of -2 and maximum of 18, to fix this we add 8 to -10cos((π/5)x) to get -10cos((π/5)x)+8 which does have a minimum of -2 and maximum of 18.
Therefore the answer is y=-10cos((π/5)x)+8. x being time in minutes and and y being the height in feet.
I hope this helps. Let me know if anything is unclear.
Answer and explanation:
Surface area of a rectangle = length * width
Surface area of a square = a² where a is length of a side
To find total surface area of the the five pieces of paper, we add up all the areas of all the shapes
Given that length of rectangle =3.5
And width = 2
Area of rectangle =3.5*2=7
Area of 3 rectangles given they are all equal = 7*3=21
Since width of rectangle equal to width of square and all sides of square are equal
Area of square = 2 *2 =4
Area of the two squares =4*2=8
Total surface area of the five plane shapes = 21+8= 29
