Find Amplitude, Period, and Phase Shift f(x)=-7sin(9x)

$f (x) = - 7 \sin (9 x)$

Use the form $a \sin (b x - c) + d$ to find the variables used to find the amplitude, period, phase shift, and vertical shift.

$a = - 7$

$b = 9$

$c = 0$

$d = 0$

Find the amplitude $| a |$ .

Amplitude: $7$

Find the period of $- 7 \sin (9 x)$ .

The period of the function can be calculated using $\frac{2 π}{| b |}$ .

$\frac{2 π}{| b |}$

Replace $b$ with $9$ in the formula for period.

$\frac{2 π}{| 9 |}$

The absolute value is the distance between a number and zero. The distance between $0$ and $9$ is $9$ .

$\frac{2 π}{9}$

Find the phase shift using the formula $\frac{c}{b}$ .

The phase shift of the function can be calculated from $\frac{c}{b}$ .

Phase Shift: $\frac{c}{b}$

Replace the values of $c$ and $b$ in the equation for phase shift.

Phase Shift: $\frac{0}{9}$

Divide $0$ by $9$ .

Phase Shift: $0$

List the properties of the trigonometric function.

Amplitude: $7$

Period: $\frac{2 π}{9}$

Phase Shift: None

Vertical Shift: None