由根号下36-x^2得 36-x^2≥0;→ -6≤x≤6.
由lgcosx得 cosx>0;则在区间(-2π,2π)内,x∈(-2π,-3π/2)∪(-π/2,π/2)∪(3π/2,2π).
∴定义域是x∈[-6,-3π/2)∪(-π/2,π/2)∪(3π/2,6]
由根号下36-x^2得 36-x^2≥0;→ -6≤x≤6.
由lgcosx得 cosx>0;则在区间(-2π,2π)内,x∈(-2π,-3π/2)∪(-π/2,π/2)∪(3π/2,2π).
∴定义域是x∈[-6,-3π/2)∪(-π/2,π/2)∪(3π/2,6]