Answer:
D) A=7, [tex]P=\frac{2\pi}{9}[/tex], PS=(0,0) is correct.
Step-by-step explanation:
Given function is [tex]f(x)=7\cos(9x)[/tex]
Compare that with formula [tex]f(x)=A\cos(Bx-C)+D[/tex]
we get:
A=7, B=9, C=0, D=0
In that formula, amplitude is given by formula |a|
Hence amplitude = |a|=|7|= 7
In that formula, period is given by formula [tex]\frac{2\pi}{B}[/tex]
Hence period = [tex]\frac{2\pi}{B}=\frac{2\pi}{9}[/tex]
Phase shift is given by formula [tex]\frac{C}{B}[/tex]
Hence phase shift = [tex]\frac{C}{B}=\frac{0}{9}=0[/tex]
So the last choice D) A=7, [tex]P=\frac{2\pi}{9}[/tex], PS=(0,0) is correct.
