已知函数y=f(x)的定义域是[0,1/4],求下列函数的定义域：（1）f[(cosx)^2 (2)f[(sinx)^2-1/2]
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(1) 0 ≤ (cosx)^2 ≤ 1/4
-1/2 ≤ cosx ≤ 1/2
π/3 ≤x ≤ 2π/3 (cos(π/3) = 1/2, cos(2π/3) = -1/2)
(2) 0 ≤ (sinx)^2-1/2 ≤ 1/4
1/2 ≤ (sinx)^2 ≤ 3/4
√2/2 ≤ sinx ≤ √3/2 或 -√3/2 ≤ sinx ≤ -√2/2
π/4 ≤ x ≤ π/3 或 -π/3 ≤ x ≤ -π/4
-1/2 ≤ cosx ≤ 1/2
π/3 ≤x ≤ 2π/3 (cos(π/3) = 1/2, cos(2π/3) = -1/2)
(2) 0 ≤ (sinx)^2-1/2 ≤ 1/4
1/2 ≤ (sinx)^2 ≤ 3/4
√2/2 ≤ sinx ≤ √3/2 或 -√3/2 ≤ sinx ≤ -√2/2
π/4 ≤ x ≤ π/3 或 -π/3 ≤ x ≤ -π/4
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