csat-suneung 2024 Q12

csat-suneung · South-Korea · csat__math 4 marks Areas by integration
For the function $f(x) = \frac{1}{9}x(x-6)(x-9)$ and a real number $t$ with $0 < t < 6$, the function $g(x)$ is defined as $$g(x) = \begin{cases} f(x) & (x < t) \\ -(x-t) + f(t) & (x \geq t) \end{cases}$$ Find the maximum area of the region enclosed by the graph of $y = g(x)$ and the $x$-axis. [4 points]
(1) $\frac{125}{4}$
(2) $\frac{127}{4}$
(3) $\frac{129}{4}$
(4) $\frac{131}{4}$
(5) $\frac{133}{4}$
For the function $f(x) = \frac{1}{9}x(x-6)(x-9)$ and a real number $t$ with $0 < t < 6$, the function $g(x)$ is defined as
$$g(x) = \begin{cases} f(x) & (x < t) \\ -(x-t) + f(t) & (x \geq t) \end{cases}$$
Find the maximum area of the region enclosed by the graph of $y = g(x)$ and the $x$-axis. [4 points]\\
(1) $\frac{125}{4}$\\
(2) $\frac{127}{4}$\\
(3) $\frac{129}{4}$\\
(4) $\frac{131}{4}$\\
(5) $\frac{133}{4}$