(3)当A≥0时,x<-A或x>A 当A<0时,x∈R (4)a-n<a<a+n (5)原式等价于x-2∠0,则-1<x<2 <x< <x<一一 4.求下列函数的定义域及它在给定点上的函数值 (1)y=f(x)=-x+-的定义域及f(-1),f(1)和f(2) (2)y=/()=√a2的定义域及/(,J(和(-2) 1 (3)=8()=c的定义域及(1),(2 (4)y=g(a)=a2tana的定义域及g(0),g ()x=2()2=sm0+c的定义域及x(-2),x(-m) (6)y=f(x)= 的定义域及f(0),f(-1)3 (3) A > 0ûßx < −A½x > A ✘ ✛✲ 0 A-A x ❡❡ A < 0ûßx ∈ R (4) a − η < x < a + η ✛a ✘ ✲ − η 0 a + ηa x ❡❡ (5) ™du x − 2 x + 1 < 0ßK−1 < x < 2 ✛ ✘✲ -1 1 2 0 x ❜ ❜ (6) − 5 3 < x < − 3 2 ½− 5 2 < x < − 7 3 ✲ ✞ ☎ ✞ ☎ -1-2-3 0 x ❡❡ ❡❡ 4. ¶eºÍ½¬ç9ß3â½:˛ºÍäµ (1) y = f(x) = −x + 1 x ½¬ç9f(−1), f(1)⁄f(2)¶ (2) y = f(x) = √ a 2 − x2½¬ç9f(0), f(a)⁄f  − a 2  ¶ (3) s = s(t) = 1 t e −t½¬ç9s(1), s(2)¶ (4) y = g(α) = α 2 tan Ὤç9g(0), g  π 4  , g  − π 4  ¶ (5) x = x(θ) = sin θ + cos 转ç9x  − π 2  , x(−π) (6) y = f(x) = 1 (x − 1)(x + 2)½¬ç9f(0), f(−1)