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问题: 高一数学题,急急!!!!!

求下列函数的定义域:
(1)y=√2cos-1
(2)y=lg(3-4sin^2x)

解答:

(1) y=√2cos-1, 2cos-1>=0, cosx >= 1/2
==> 定义域: 2n*Pi -Pi/3 <= x <= 2n*Pi +Pi/3
(2) y=lg(3-4sin^2x), 3-4sin^2x >0, sin^2x < 3/4
-(√3)/2 < sinx < (√3)/2
==> 定义域: n*Pi -Pi/3 <= x <= n*Pi +Pi/3