数学已知函数f(x)=sin(x+θ)+cos(x+θ)的定义域为R.(1)当θ=π/2时,求f(x)的单调递增区间.
来源:学生作业帮 编辑:百度作业网作业帮 分类:数学作业 时间:2024/07/09 04:16:14
数学已知函数f(x)=sin(x+θ)+cos(x+θ)的定义域为R.(1)当θ=π/2时,求f(x)的单调递增区间.
RT
RT
![数学已知函数f(x)=sin(x+θ)+cos(x+θ)的定义域为R.(1)当θ=π/2时,求f(x)的单调递增区间.](/uploads/image/z/1848114-18-4.jpg?t=%E6%95%B0%E5%AD%A6%E5%B7%B2%E7%9F%A5%E5%87%BD%E6%95%B0f%28x%29%3Dsin%28x%2B%CE%B8%EF%BC%89%2Bcos%EF%BC%88x%2B%CE%B8%29%E7%9A%84%E5%AE%9A%E4%B9%89%E5%9F%9F%E4%B8%BAR.%EF%BC%881%EF%BC%89%E5%BD%93%CE%B8%3D%CF%80%2F2%E6%97%B6%2C%E6%B1%82f%28x%29%E7%9A%84%E5%8D%95%E8%B0%83%E9%80%92%E5%A2%9E%E5%8C%BA%E9%97%B4.)
f(x)=sin(x+θ)+cos(x+θ)
= √2[√2/2sin(x+θ)+√2/2cos(x+θ)]
=√2[sin(x+θ)cosπ/4+cos(x+θ)sinπ/4]
=√2sin(x+θ+π/4)
当 θ=π/2时,f(x) =√2sin(x+θ+π/4)
=√2sin(x+3π/4)
当 x+3π/4 ∈[2kπ-π/2,2kπ+π/2]时,f(x)单调递增;
此时 x ∈[2kπ-5π/4,2kπ-π/4] 其中 k ∈Z.
= √2[√2/2sin(x+θ)+√2/2cos(x+θ)]
=√2[sin(x+θ)cosπ/4+cos(x+θ)sinπ/4]
=√2sin(x+θ+π/4)
当 θ=π/2时,f(x) =√2sin(x+θ+π/4)
=√2sin(x+3π/4)
当 x+3π/4 ∈[2kπ-π/2,2kπ+π/2]时,f(x)单调递增;
此时 x ∈[2kπ-5π/4,2kπ-π/4] 其中 k ∈Z.
数学已知函数f(x)=sin(x+θ)+cos(x+θ)的定义域为R.(1)当θ=π/2时,求f(x)的单调递增区间.
数学已知函数f(x)=sin(x+θ)+cos(x+θ)的定义域为R.(1)当θ=0时,求f(x)的单调递增区间.(2)
已知函数f(x)=sin(x+θ)+cos(x+θ)的定义域为R.(1)当θ=0时,求f(x)的单调递增区间.(2)若θ
已知函数f(x)=cos(-x/2)+sin(π-x/2),x∈R.(1 )求函数f(x)的最小正周期及单调递增区间
已知函数f(x)=sin(x+a)+cos(x+a)的定义域为R (1)当a=0时,求f(x)的单调增区间
已知函数f(x)=a(2cos^2x/2+sinx)+b (1当a=1时,求f(x)的单调递增区间.
已知函数f(x)=cos^2x+sinxcosx,求f(x)的单调递增区间
已知函数f(x)=lg[2sin(2x-派/3)-1],求f(x)定义域.求f(x)的单调递增区间.
已知定义域为R的函数f(x)满足f(-x)=-f(x+4),当x>2时,f(x)单调递增.如果x1+x2
已知函数f(x)=(cosx-sinx)cos(兀+x),x属于R.(1)求f(x)的最小正周期和单调递增区间
已知a∈R,函数f(x)=x|x-a|,(1)当a=2时,写出y=f(x)的单调递增区间;
已知定义域为R的函数f(x)满足f(-x)=-f(4+x),且函数f(x)在区间(2,正无穷)上单调递增