5x + 10y = 50
x + y = 8
x = 8 - y
5*(8-y) + 10y = 50
40 - 5y + 10y = 50
10y - 5y = 50 - 40
5y = 10
y = 2
x + y = 8
x + 2 = 8
x = 8 - 2
x = 6
She has 6 nickels and 2 dimes
The number of gallons of water in the tank at t=10 is
... W(10) = 160,000 -10(8000 -10) = 80100
The number of gallons of water in the tank at t=10.5 is
... W(10.5) = 160,000 -10.5(8000 -10.5) = 76110.25
The rate of change over the interval is
... (W(10.5) - W(10))/(10.5 - 10) = (76110.25 - 80100)/(0.5) = -7979.5
The average rate of change in the number of gallons of water in the tank over the interval is -7979.5 gal/min.
The sign is negative, so the amount of water is decreasing.
Answer:
-1/root2
Step-by-step explanation:
7pi/4 radians is the same as -pi/4 radians
sin(-pi/4) is -sin(pi/4) = -1/root2