What is the amplitude, period, and phase shift of f(x) = −3 sin(4x − π) − 5?

Amplitude = −3; period = 2π; phase shift: x equals pi over four
Amplitude = 3; period = pi over two; phase shift: x equals pi over four
Amplitude = −3; period = 2π; phase shift: x equals negative pi over four
Amplitude = 3; period = pi over two; phase shift: x equals negative pi over four

Respuesta :

Answer:

2nd choice.

Step-by-step explanation:

Let's compare the following:

[tex]f(x)=a\sin(b(x-c))+d[/tex] to

[tex]f(x)=-3\sin(4x-\pi))-5[/tex].

They are almost in the same form.

The amplitude is |a|, so it isn't going to be negative.

The period is [tex]\frac{2\pi}{|b|}[/tex].

The phase shift is [tex]c[/tex].

If c is positive it has been shifted right c units.

If c is negative it has been shifted left c units.

d is the vertical shift.

If d is negative, it has been moved down d units.

If d is positive, it has been moved up d units.

So we already know two things:

The amplitude is |a|=|-3|=3.

The vertical shift is d=-5 which means it was moved down 5 units from the parent function.

Now let's find the others.

I'm going to factor out 4 from [tex]4x-\pi[/tex].

Like this:

[tex]4(x-\frac{\pi}{4})[/tex]

Now if you compare this to [tex]b(x-c)[/tex]

then b=4 so the period is [tex]\frac{2\pi}{4}=\frac{\pi}{2}[/tex].

Also in place of c you see [tex]\frac{\pi}{4}[/tex] which means the phase shift is [tex]\frac{\pi}{4}[/tex].

The second choice is what we are looking for.

Answer: Second Option

Amplitude = 3; period = pi over two; phase shift: x equals pi over four

Step-by-step explanation:

By definition the sinusoidal function has the following form:

[tex]f(x) = asin(bx - c) +k[/tex]

Where

[tex]| a |[/tex] is the Amplitude of the function

[tex]\frac{2\pi}{b}[/tex] is the period of the function

[tex]-\frac{c}{b}[/tex] is the phase shift

In this case the function is:

[tex]f(x) = -3 sin(4x - \pi) - 5[/tex]

Therefore

[tex]Amplitude=|a|=3[/tex]

[tex]Period =\frac{2\pi}{b} = \frac{2\pi}{4}=\frac{\pi}{2}[/tex]

[tex]phase\ shift = -\frac{(-\pi)}{4}=\frac{\pi}{4}[/tex]