Precalculus Examples

$f (x) = x^{5} - x^{4} + 8 x^{3} - 8 x^{2} - 15 x + 15$ ; $[1.2, 1.3]$

Step 1

Write $f (x) = x^{5} - x^{4} + 8 x^{3} - 8 x^{2} - 15 x + 15$ as an equation.

$y = x^{5} - x^{4} + 8 x^{3} - 8 x^{2} - 15 x + 15$

Step 2

Substitute using the average rate of change formula.

Tap for more steps...

Step 2.1

The average rate of change of a function can be found by calculating the change in $y$ values of the two points divided by the change in $x$ values of the two points.

$\frac{f (1.3) - f (1.2)}{(1.3) - (1.2)}$

Step 2.2

Substitute the equation $y = x^{5} - x^{4} + 8 x^{3} - 8 x^{2} - 15 x + 15$ for $f (1.3)$ and $f (1.2)$ , replacing $x$ in the function with the corresponding $x$ value.

$\frac{({(1.3)}^{5} - {(1.3)}^{4} + 8 {(1.3)}^{3} - 8 {(1.3)}^{2} - 15 \cdot 1.3 + 15) - ({(1.2)}^{5} - {(1.2)}^{4} + 8 {(1.2)}^{3} - 8 {(1.2)}^{2} - 15 \cdot 1.2 + 15)}{(1.3) - (1.2)}$

Step 3

Simplify the expression.

Tap for more steps...

Step 3.1

Simplify the numerator.

Tap for more steps...

Step 3.1.1

Raise $1.3$ to the power of $5$ .

$\frac{3.71293 - {1.3}^{4} + 8 \cdot {1.3}^{3} - 8 \cdot {1.3}^{2} - 15 \cdot 1.3 + 15 - ({1.2}^{5} - {1.2}^{4} + 8 \cdot {1.2}^{3} - 8 \cdot {1.2}^{2} - 15 \cdot 1.2 + 15)}{1.3 - (1.2)}$

Step 3.1.2

Raise $1.3$ to the power of $4$ .

$\frac{3.71293 - 1 \cdot 2.8561 + 8 \cdot {1.3}^{3} - 8 \cdot {1.3}^{2} - 15 \cdot 1.3 + 15 - ({1.2}^{5} - {1.2}^{4} + 8 \cdot {1.2}^{3} - 8 \cdot {1.2}^{2} - 15 \cdot 1.2 + 15)}{1.3 - (1.2)}$

Step 3.1.3

Multiply $- 1$ by $2.8561$ .

$\frac{3.71293 - 2.8561 + 8 \cdot {1.3}^{3} - 8 \cdot {1.3}^{2} - 15 \cdot 1.3 + 15 - ({1.2}^{5} - {1.2}^{4} + 8 \cdot {1.2}^{3} - 8 \cdot {1.2}^{2} - 15 \cdot 1.2 + 15)}{1.3 - (1.2)}$

Step 3.1.4

Raise $1.3$ to the power of $3$ .

$\frac{3.71293 - 2.8561 + 8 \cdot 2.197 - 8 \cdot {1.3}^{2} - 15 \cdot 1.3 + 15 - ({1.2}^{5} - {1.2}^{4} + 8 \cdot {1.2}^{3} - 8 \cdot {1.2}^{2} - 15 \cdot 1.2 + 15)}{1.3 - (1.2)}$

Step 3.1.5

Multiply $8$ by $2.197$ .

$\frac{3.71293 - 2.8561 + 17.576 - 8 \cdot {1.3}^{2} - 15 \cdot 1.3 + 15 - ({1.2}^{5} - {1.2}^{4} + 8 \cdot {1.2}^{3} - 8 \cdot {1.2}^{2} - 15 \cdot 1.2 + 15)}{1.3 - (1.2)}$

Step 3.1.6

Raise $1.3$ to the power of $2$ .

$\frac{3.71293 - 2.8561 + 17.576 - 8 \cdot 1.69 - 15 \cdot 1.3 + 15 - ({1.2}^{5} - {1.2}^{4} + 8 \cdot {1.2}^{3} - 8 \cdot {1.2}^{2} - 15 \cdot 1.2 + 15)}{1.3 - (1.2)}$

Step 3.1.7

Multiply $- 8$ by $1.69$ .

$\frac{3.71293 - 2.8561 + 17.576 - 13.52 - 15 \cdot 1.3 + 15 - ({1.2}^{5} - {1.2}^{4} + 8 \cdot {1.2}^{3} - 8 \cdot {1.2}^{2} - 15 \cdot 1.2 + 15)}{1.3 - (1.2)}$

Step 3.1.8

Multiply $- 15$ by $1.3$ .

$\frac{3.71293 - 2.8561 + 17.576 - 13.52 - 19.5 + 15 - ({1.2}^{5} - {1.2}^{4} + 8 \cdot {1.2}^{3} - 8 \cdot {1.2}^{2} - 15 \cdot 1.2 + 15)}{1.3 - (1.2)}$

Step 3.1.9

Simplify each term.

Tap for more steps...

Step 3.1.9.1

Raise $1.2$ to the power of $5$ .

$\frac{3.71293 - 2.8561 + 17.576 - 13.52 - 19.5 + 15 - (2.48832 - {1.2}^{4} + 8 \cdot {1.2}^{3} - 8 \cdot {1.2}^{2} - 15 \cdot 1.2 + 15)}{1.3 - (1.2)}$

Step 3.1.9.2

Raise $1.2$ to the power of $4$ .

$\frac{3.71293 - 2.8561 + 17.576 - 13.52 - 19.5 + 15 - (2.48832 - 1 \cdot 2.0736 + 8 \cdot {1.2}^{3} - 8 \cdot {1.2}^{2} - 15 \cdot 1.2 + 15)}{1.3 - (1.2)}$

Step 3.1.9.3

Multiply $- 1$ by $2.0736$ .

$\frac{3.71293 - 2.8561 + 17.576 - 13.52 - 19.5 + 15 - (2.48832 - 2.0736 + 8 \cdot {1.2}^{3} - 8 \cdot {1.2}^{2} - 15 \cdot 1.2 + 15)}{1.3 - (1.2)}$

Step 3.1.9.4

Raise $1.2$ to the power of $3$ .

$\frac{3.71293 - 2.8561 + 17.576 - 13.52 - 19.5 + 15 - (2.48832 - 2.0736 + 8 \cdot 1.728 - 8 \cdot {1.2}^{2} - 15 \cdot 1.2 + 15)}{1.3 - (1.2)}$

Step 3.1.9.5

Multiply $8$ by $1.728$ .

$\frac{3.71293 - 2.8561 + 17.576 - 13.52 - 19.5 + 15 - (2.48832 - 2.0736 + 13.824 - 8 \cdot {1.2}^{2} - 15 \cdot 1.2 + 15)}{1.3 - (1.2)}$

Step 3.1.9.6

Raise $1.2$ to the power of $2$ .

$\frac{3.71293 - 2.8561 + 17.576 - 13.52 - 19.5 + 15 - (2.48832 - 2.0736 + 13.824 - 8 \cdot 1.44 - 15 \cdot 1.2 + 15)}{1.3 - (1.2)}$

Step 3.1.9.7

Multiply $- 8$ by $1.44$ .

$\frac{3.71293 - 2.8561 + 17.576 - 13.52 - 19.5 + 15 - (2.48832 - 2.0736 + 13.824 - 11.52 - 15 \cdot 1.2 + 15)}{1.3 - (1.2)}$

Step 3.1.9.8

Multiply $- 15$ by $1.2$ .

$\frac{3.71293 - 2.8561 + 17.576 - 13.52 - 19.5 + 15 - (2.48832 - 2.0736 + 13.824 - 11.52 - 18 + 15)}{1.3 - (1.2)}$

Step 3.1.10

Subtract $2.0736$ from $2.48832$ .

$\frac{3.71293 - 2.8561 + 17.576 - 13.52 - 19.5 + 15 - (0.41472 + 13.824 - 11.52 - 18 + 15)}{1.3 - (1.2)}$

Step 3.1.11

Add $0.41472$ and $13.824$ .

$\frac{3.71293 - 2.8561 + 17.576 - 13.52 - 19.5 + 15 - (14.23872 - 11.52 - 18 + 15)}{1.3 - (1.2)}$

Step 3.1.12

Subtract $11.52$ from $14.23872$ .

$\frac{3.71293 - 2.8561 + 17.576 - 13.52 - 19.5 + 15 - (2.71872 - 18 + 15)}{1.3 - (1.2)}$

Step 3.1.13

Subtract $18$ from $2.71872$ .

$\frac{3.71293 - 2.8561 + 17.576 - 13.52 - 19.5 + 15 - (- 15.28128 + 15)}{1.3 - (1.2)}$

Step 3.1.14

Add $- 15.28128$ and $15$ .

$\frac{3.71293 - 2.8561 + 17.576 - 13.52 - 19.5 + 15 - - 0.28128}{1.3 - (1.2)}$

Step 3.1.15

Multiply $- 1$ by $- 0.28128$ .

$\frac{3.71293 - 2.8561 + 17.576 - 13.52 - 19.5 + 15 + 0.28128}{1.3 - (1.2)}$

Step 3.1.16

Subtract $2.8561$ from $3.71293$ .

$\frac{0.85683 + 17.576 - 13.52 - 19.5 + 15 + 0.28128}{1.3 - (1.2)}$

Step 3.1.17

Add $0.85683$ and $17.576$ .

$\frac{18.43283 - 13.52 - 19.5 + 15 + 0.28128}{1.3 - (1.2)}$

Step 3.1.18

Subtract $13.52$ from $18.43283$ .

$\frac{4.91283 - 19.5 + 15 + 0.28128}{1.3 - (1.2)}$

Step 3.1.19

Subtract $19.5$ from $4.91283$ .

$\frac{- 14.58717 + 15 + 0.28128}{1.3 - (1.2)}$

Step 3.1.20

Add $- 14.58717$ and $15$ .

$\frac{0.41283 + 0.28128}{1.3 - (1.2)}$

Step 3.1.21

Add $0.41283$ and $0.28128$ .

$\frac{0.69411}{1.3 - (1.2)}$

Step 3.2

Simplify the denominator.

Tap for more steps...

Step 3.2.1

Multiply $- 1$ by $1.2$ .

$\frac{0.69411}{1.3 - 1.2}$

Step 3.2.2

Subtract $1.2$ from $1.3$ .

$\frac{0.69411}{0.1}$

Step 3.3

Divide $0.69411$ by $0.1$ .

$6.9411$