Step-by-step explanation:
the answer as shown in the photo
<h3>
Answer: Choice B</h3>
Explanation:
The general template of a sine function is
y = Asin(B(x-C))+D
The value of B is the only thing that determines the period T. We ignore every other term.
It turns out that T = 2pi/B which can be solved to B = 2pi/T
Plug in the given period of T = 8pi and compute to get
B = 2pi/T
B = (2pi)/(8pi)
B = 2/8
B = 1/4
This means that the term out front of the x is 1/4 and the equation must be
which matches with answer choice B.
When multiplying numbers a negative number will make a positive into a negative. Yet if multiplied again by another negative it will cancel out or make it positive again. Seeing as answer c has only one negative it's the correct answer.
Wouldn't you just count back 30 minutes from 10:08?
If you round up to 10:10, it's a little easier. Picture an analog clock in your head. Every big number is five minutes, and every two is ten minutes. If we put it back to the 12, that's ten minutes back. Twenty minutes earlier from that would be 9:40. Since we added two minutes to make it easier, we've got to subtract those two minutes. So, the starting time would be 9:38.
I hope this isn't too confusing.