2011安徽高考数学理科第一大题选择题9 10怎么做?很急,谢谢。
9.已知函数f(x)=sin(2x+θ),其中θ为实数,若f(x);F(π),则f(x)的单调递增区间为
解析:∫函数f(x)=sin(2x+θ),f (x) < =|f(π/6)|对x ∈ r成立。
∴f(π/6)=sin(π/3+θ)<;=1== >θ=π/6 = = & gt;f(x)= sin(2x+π/6)= = & gt;f(π/2)& lt;f(π)
f(π/6)=-1 & lt;= sin(π/3+θ)= = & gt;θ=-5π/6 = = & gt;f(x)= sin(2x-5π/6)= = & gt;f(π/2)>f(π)
2kπ-π/2 & lt;=(2x-5π/6)& lt;= 2kπ+π/2 = = & gt;kπ+π/6 & lt;= x & lt=kπ+2π/3
∴f(x的单调递增区间)为kπ+π/6
选项c
10、F(x)=ax^m*(1-x)^n [0,1]
f'(x)=amx^(m-1)*(1-x)^n-ax^m*n(1-x)^(n-1)=0
amx^(m-1)*(1-x)^n=ax^m*n(1-x)^(n-1)
1 = NX/(m-MX)= = & gt;x=m/(m+n)
答:极值点x=1/2
B: x=1/3
C:x=2/3
D:x=3/4
从图中可以看出,极值点x