The basic function you would use to figure out the value of the stock as time passes is:
A = 5,000(1.08)^t
This reflects the initial investment of $5,000 growing at an 8% increase per week.
Another valid response that represents the same concept is:
A = P(1 + r)^t, where P is the principal amount ($5,000), r is the rate of increase (0.08), and t is time in weeks. In this case, it can be plugged in as A = 5,000(1 + 0.08)^t, which simplifies to A = 5,000(1.08)^t.
So both A = 5,000(1.08)^t and A = P(1 + r)^t are correct representations of the situation.