Answer:
0.0048cm/s
Step-by-step explanation:
Volume of the spherical balloon is expressed as;
dV/dt = dV/dr * dr/dt
Given
dV/dt = 5cm³/s
dV/dr = 4πr²
Since V = 972picm³
972π = 4/3πr³
972 = 4/3r³
4r³ = 972 * 3
r³ = (972 *3)/4
r³ = 729
r = ∛729
r = 9cm
dV/dr = 4π(9)²
dV/dr = 324π
dV/dt = dV/dr * dr/dt
5 = 324πdr/dt
dr/dt = 5/324π
dr/dt = 5/324(3.14)
dr/dt = 5/1017.36
dr/dt = 0.0048cm/s
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Work Shown:
Plug in x = 0
This indicates that (0,1) is on the curve. This is the y intercept.
Do the same for x = 2
So we know that (2,81) is another point on this curve.
We need to find the slope of the line through (0,1) and (2,81) to get the slope of the secant line we want.
The slope of the line through (0,1) and (2,81) is m = 40. This value of m is exactly the slope of the secant line your teacher is asking for. This is why the answer is choice C.
