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已知函数f(x)=sin(x+π/6)+sin(x-π/6)+cosx+a(a属于R,a是常数)(1)求函数f(x)的最
题目内容:
已知函数f(x)=sin(x+π/6)+sin(x-π/6)+cosx+a(a属于R,a是常数)
(1)求函数f(x)的最小正周期
(2)若x属于[-π/2,π/2]时,最大值最小值之和为√3,求a的值.优质解答
1、
f(x)=sinxcosπ/6+cosxsinπ/6+sinxcosπ/6-cosxsinπ/6+cosx+a
=2sinxcosπ/6+cosx+a
=√3sinx+cosx+a
=√[(√3)²+1²]sin(x+z)+a
=2sin(x+z)+a
其中tanz=1/√3
所以T=2π/1=2π
2、
tanz=1/√3
z=π/6
f(x)=2sin(x+π/6)+a
-π/2
(1)求函数f(x)的最小正周期
(2)若x属于[-π/2,π/2]时,最大值最小值之和为√3,求a的值.
优质解答
f(x)=sinxcosπ/6+cosxsinπ/6+sinxcosπ/6-cosxsinπ/6+cosx+a
=2sinxcosπ/6+cosx+a
=√3sinx+cosx+a
=√[(√3)²+1²]sin(x+z)+a
=2sin(x+z)+a
其中tanz=1/√3
所以T=2π/1=2π
2、
tanz=1/√3
z=π/6
f(x)=2sin(x+π/6)+a
-π/2
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