gaokao 2019 Q11

gaokao · China · national-I-science Trig Graphs & Exact Values
11. Regarding the function $f ( x ) = \sin | x | + | \sin x |$, there are four conclusions:
(1) $f ( x )$ is an even function
(2) $f ( x )$ is monotonically increasing on the interval $\left( \frac { \pi } { 2 } , \pi \right)$
(3) $f ( x )$ has 4 zeros on $[ - \pi , \pi ]$
(4) The maximum value of $f ( x )$ is 2
The numbers of all correct conclusions are
A. (1)(2)(4)
B. (2)(4)
C. (1)(4)
D. (1)(3)
C
11. Regarding the function $f ( x ) = \sin | x | + | \sin x |$, there are four conclusions:\\
(1) $f ( x )$ is an even function\\
(2) $f ( x )$ is monotonically increasing on the interval $\left( \frac { \pi } { 2 } , \pi \right)$\\
(3) $f ( x )$ has 4 zeros on $[ - \pi , \pi ]$\\
(4) The maximum value of $f ( x )$ is 2

The numbers of all correct conclusions are\\
A. (1)(2)(4)\\
B. (2)(4)\\
C. (1)(4)\\
D. (1)(3)