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17/2 = 8.5 hours per week
8.5 x 5 = 42.5 hours in 5 weeks
area of a circle is PI x r^2
2 = d/2 = 5.4/2 = 2.7 cm
using 3.14 for PI
3.14 x 2.7^2 = 22.89 square inches
360 degree in a circle, shaded area is 180 degree, which is 50%
so 22.89 x .5 = 11.45 cm^2
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.
Let x, represent the number of minutes and y represents the number of gallons of water in the tub, then the ordered pairs (2, 30) and (5, 12) satisfies the equation.
Therefore the equation is given by: (y - 30)/(x - 2) = (12 - 30)/(5 - 2)
(y - 30)/(x - 2) = -18/3 x = -6
y - 30 = -6(x - 2) = -6x + 12
y = -6x + 42
Required equation is y + 6x = 42.
