Compare the estimated average rates of change of the functions f(x)=3x−4−−−−−−√

and g(x)=2x−4/3−−−−−√3
over the interval [2,3]
. State the difference in the estimated average rates of change to the nearest tenth.(1 point)
The difference between the estimated average rates of change is approximately
.

1 answer

To find the estimated average rates of change of the functions \( f(x) = \sqrt{3x - 4} \) and \( g(x) = \sqrt[3]{2x - 4} \) over the interval \([2, 3]\), we can use the formula for the average rate of change over the interval \([a, b]\):

\[ \text{Average rate of change} = \frac{f(b) - f(a)}{b - a} \]

Step 1: Calculate \( f(2) \) and \( f(3) \)

  1. Calculate \( f(2) \): \[ f(2) = \sqrt{3(2) - 4} = \sqrt{6 - 4} = \sqrt{2} \]

  2. Calculate \( f(3) \): \[ f(3) = \sqrt{3(3) - 4} = \sqrt{9 - 4} = \sqrt{5} \]

Step 2: Calculate the average rate of change for \( f(x) \)

Using the values obtained: \[ \text{Average rate of change of } f = \frac{f(3) - f(2)}{3 - 2} = \frac{\sqrt{5} - \sqrt{2}}{1} = \sqrt{5} - \sqrt{2} \]

Step 3: Calculate \( g(2) \) and \( g(3) \)

  1. Calculate \( g(2) \): \[ g(2) = \sqrt[3]{2(2) - 4} = \sqrt[3]{4 - 4} = \sqrt[3]{0} = 0 \]

  2. Calculate \( g(3) \): \[ g(3) = \sqrt[3]{2(3) - 4} = \sqrt[3]{6 - 4} = \sqrt[3]{2} \]

Step 4: Calculate the average rate of change for \( g(x) \)

Using the values obtained: \[ \text{Average rate of change of } g = \frac{g(3) - g(2)}{3 - 2} = \frac{\sqrt[3]{2} - 0}{1} = \sqrt[3]{2} \]

Step 5: Calculate the difference in estimated average rates of change

Now we need to calculate the difference: \[ \text{Difference} = (\sqrt{5} - \sqrt{2}) - \sqrt[3]{2} \]

Step 6: Numerical Approximation

We can approximate these values:

  • \( \sqrt{5} \approx 2.236 \)
  • \( \sqrt{2} \approx 1.414 \)
  • \( \sqrt[3]{2} \approx 1.260 \)

Substituting these approximations into the expression for the difference: \[ \text{Difference} \approx (2.236 - 1.414) - 1.260 \] Calculating \( 2.236 - 1.414 \) gives approximately \( 0.822 \).

Now we find: \[ 0.822 - 1.260 \approx -0.438 \]

Final step: Rounding to the nearest tenth

The difference to the nearest tenth is: \[ \text{Difference} \approx -0.4 \]

Thus, the final answer is: \[ \text{The difference between the estimated average rates of change is approximately } -0.4. \]