OG详解-OG2 数学2 Q17

Choice D is correct. They-intercept of a graph in the ty-plane is the point where t = 0. For the given function f, they-intercept of the graph of y = f (t) in the ty-plane can be found by substituting 0  for t in the equation y = 8,000 (0.65)^t , which gives y = 8,000 (0.65)⁰. This is equivalent to y = 8,000 (1), or y = 8,000. Therefore, they-intercept of the graph of y = f (t) is (0, 8,000). It’s given that the function f  models the number of coupons a company sent to their customers at the end of each year. Therefore, f(t) represents the estimated number of coupons the company sent to their customers at the end of each year. It’s also given that t represents the number of years since the end of  1998. Therefore, t = 0 represents 0 years since the end of 1998, or the end of1998. Thus, the best interpretation of they-intercept of the graph of y = f (t) is that the estimated number of coupons the company sent to their customers at the end of  1998 was 8,000.
Choice A is incorrect and may result from conceptual or calculation errors.
Choice B is incorrect and may result from conceptual or calculation errors.
Choice C is incorrect and may result from conceptual or calculation errors.