Answer:
-875/79
Step-by-step explanation:
Second is the answer is correct (99% sure)
After Applying Laws of Exponents we can write as 
<h3>What is law of exponents ?</h3>
The exponent of a number indicates how many times a number has been multiplied by itself. For instance, 34 indicates that we have multiplied 3 four times. Its full form is 3 3 3 3. Exponent is another name for a number's power. A whole number, fraction, negative number, or decimal are all acceptable.
<h3>How are powers of powers multiplied?</h3>
Exponents with distinct bases and the same powers can be multiplied by multiplying the bases and writing the power outside of the brackets.
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The general equation of the cosine function is
y = a cos nθ
where a is the amplitude
And n = 2π/period
by comparing the general equation with the given equation which is
<span>Y = 5 cos 2</span>θ
∴ a = 5 and n = 2
∴ period = 2π/n = 2π/2 = π
∴ The amplitude = 5 and the period = π
So, the correct answer is the second option
<span>Period pi, radians; amplitude: 5</span>