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
2/5 (-7) 5/2 as you know 2/5 x 5/2 = 1
so 1 x (-7) = -7
so the asnwer is -7
X = 72 and it's a scalene triangle
37^0 = 1
Any number to the 0 exponent is equal 1, except 0
Answer
1