ANSWER
The correct choice is A.
EXPLANATION
The given cosine function is:

This function has an amplitude of 2.
Hence it must have range,
-2≤f(t)≤2
It has a period of

Hence the function must complete one cycle on the interval,
[0,½π],
[½π,π],
etc.
The negative sign shows a reflection in the y-axis but since the cosine function is even, the function retraces itself.
The correct choice is A
Answer:
1/10 is the simplest form
1 = Hundred tens of thousandths.
0 = tens of thousandths.
6 = thousandths.
5 = hundredths.
3 = tenths.
4 = units.
The first decimal place has the digit 0
the second decimal place has the digit 7
the third decimal place has the digit ....either 1 or 2.
this depends on the forth one, if it was 5 or higher, the third digit would be 2
since the fourth digit is 3, which is lower than 5, we don't have to change the third digit : it remains a "1"
so the answer is 0.071
They all add up to 2.5 maybe u have to simplify?