Answer:
0.6 or 
Step-by-step explanation:
Using the Pythagorean theorem (
) we get that the hypotenuse is 5.
so the cos V is adjacent over the hypotenuse. so if adjacent is 3 and hypotenuse is 5, the answer is
which equals 0.6 in decimal form.
<span>The function which has a constant halving time is in the following form
</span>

Where: A₀ is the <span>initial amount
h is the half life time or the halving time.
</span><span> t is the time
</span> A(t) <span>the amount<span> that remains at time t
</span></span>
The previous function represents an Exponential decay<span> function.
</span>
so, The correct answer is option B. <span>
Exponential decay</span>