OG详解-OG8 数学1 Q26

Choice B is correct. For the function f, since the base of the exponent, 1.25, is greater than 1, the value of (1.25)^x  increases as x increases. Therefore, the value of 18(1.25)^x and the value of 18(1.25)^x +41 also increase as x increases. Since f is therefore an increasing function where x ≥ 0, the function f has no maximum value. For the function g, since the base of the exponent, 0.73, is less than 1, the value of (0.73)^x  decreases as x increases. Therefore, the value of 9(0.73)x  also decreases as x increases. It follows that the maximum value of g(x) for x ≥ 0 occurs when x = 0. Substituting 0 for x in the function g yields g(0)= 9(0.73)⁰ , which is equivalent to g(0)= 9(1), or g(0)= 9. Therefore, the maximum value of g(x) for x ≥ 0 is 9, which appears as a coefficient in equation II. So, of the two equations given, only II displays, as a constant or coefficient, the maximum value of the function it defines, where x ≥ 0.
Choice A is incorrect and may result from conceptual or calculation errors. Choice C is incorrect and may result from conceptual or calculation errors. Choice D is incorrect and may result from conceptual or calculation errors.