which of the following is true for (f(x)=5cos(x)+1)?\nthe period of the function is (10pi).\nthe function…

which of the following is true for (f(x)=5cos(x)+1)?\nthe period of the function is (10pi).\nthe function has an amplitude of 2.5.\na zero of the function is ((\frac{pi}{2},0)).\nthe range of the function is the set of real numbers (-4leq yleq6).
Answer
Explanation:
Step1: Recall period formula for cosine
For $y = A\cos(Bx)+C$, period $T=\frac{2\pi}{|B|}$. Here $B = 1$, so $T = 2\pi\neq10\pi$.
Step2: Recall amplitude formula for cosine
Amplitude of $y=A\cos(Bx)+C$ is $|A|$. Here $A = 5$, amplitude is $5\neq2.5$.
Step3: Check for zero - point
Set $f(x)=0$, so $5\cos(x)+1 = 0$, then $\cos(x)=-\frac{1}{5}$. When $x = \frac{\pi}{2}$, $\cos(\frac{\pi}{2})=0$, so $(\frac{\pi}{2},0)$ is not a zero.
Step4: Find the range
The range of $\cos(x)$ is $[- 1,1]$. For $y = 5\cos(x)+1$, when $\cos(x)=-1$, $y=5\times(-1)+1=-4$; when $\cos(x)=1$, $y=5\times1 + 1=6$. So the range is $-4\leq y\leq6$.
Answer:
The range of the function is the set of real numbers $-4\leq y\leq6$.