Given [tex]\( g(t) = -(t-1)^2 + 5 \)[/tex], what is the average rate of change of [tex]\( g \)[/tex] over the interval [tex]\( -4 \leq t \leq 5 \)[/tex]?



Answer :

Sure, let's find the average rate of change of the function [tex]\( g(t) = -(t-1)^2 + 5 \)[/tex] over the interval [tex]\([-4, 5]\)[/tex].

### Step 1: Evaluate [tex]\( g(t) \)[/tex] at [tex]\( t = -4 \)[/tex]

We need to substitute [tex]\( t = -4 \)[/tex] into the function:

[tex]\[ g(-4) = -(-4 - 1)^2 + 5 \][/tex]

First, calculate [tex]\((-4 - 1)\)[/tex]:

[tex]\[ -4 - 1 = -5 \][/tex]

Then, square this result:

[tex]\[ (-5)^2 = 25 \][/tex]

Now, negate that result:

[tex]\[ -25 \][/tex]

Finally, add 5:

[tex]\[ -25 + 5 = -20 \][/tex]

So, [tex]\( g(-4) = -20 \)[/tex].

### Step 2: Evaluate [tex]\( g(t) \)[/tex] at [tex]\( t = 5 \)[/tex]

Next, substitute [tex]\( t = 5 \)[/tex] into the function:

[tex]\[ g(5) = -(5 - 1)^2 + 5 \][/tex]

First, calculate [tex]\(5 - 1\)[/tex]:

[tex]\[ 5 - 1 = 4 \][/tex]

Then, square this result:

[tex]\[ 4^2 = 16 \][/tex]

Now, negate that result:

[tex]\[ -16 \][/tex]

Finally, add 5:

[tex]\[ -16 + 5 = -11 \][/tex]

So, [tex]\( g(5) = -11 \)[/tex].

### Step 3: Calculate the Average Rate of Change

The average rate of change of the function over the interval [tex]\([-4, 5]\)[/tex] is given by the formula:

[tex]\[ \frac{g(t_2) - g(t_1)}{t_2 - t_1} \][/tex]

Substitute [tex]\(t_1 = -4\)[/tex] and [tex]\(t_2 = 5\)[/tex]:

[tex]\[ \frac{g(5) - g(-4)}{5 - (-4)} \][/tex]

We already found [tex]\(g(5) = -11\)[/tex] and [tex]\(g(-4) = -20\)[/tex]:

[tex]\[ \frac{-11 - (-20)}{5 - (-4)} \][/tex]

Simplify the numerator [tex]\(-11 - (-20)\)[/tex]:

[tex]\[ -11 + 20 = 9 \][/tex]

Simplify the denominator [tex]\(5 - (-4)\)[/tex]:

[tex]\[ 5 + 4 = 9 \][/tex]

Thus, the fraction becomes:

[tex]\[ \frac{9}{9} = 1 \][/tex]

So, the average rate of change of [tex]\( g(t) \)[/tex] over the interval [tex]\([-4, 5]\)[/tex] is [tex]\( 1.0 \)[/tex].

### Final Answer

[tex]\[ \boxed{1.0} \][/tex]