函数f(x)f(x)在(a,b)(a,b)和(c,d)(c,d)都是增函数,若x1∈(a,b),x2∈(c,d)x1∈(a,b),x2∈(c,d),且x1<x2x1<x2那么( )。单项选择题选项:
A.f(x1)f(x1)$f\left( {{x}_{1}} \right)<f\left( {{x}_{2}}="" \right)$<="" label=""> B.f(x1)>f(x2)f(x1)>f(x2) C.f(x1)=f(x2)f(x1)=f(x2) D.无法确定正确答案D
函数f(x)f(x)在(a,b)(a,b)和(c,d)(c,d)都是增函数,若x1∈(a,b),x2∈(c,d)x1∈(a,b),x2∈(c,d),且x1<x2x1<x2那么( )。单项选择题选项:
A.f(x1)f(x1)$f\left( {{x}_{1}} \right)<f\left( {{x}_{2}}="" \right)$<="" label=""> B.f(x1)>f(x2)f(x1)>f(x2) C.f(x1)=f(x2)f(x1)=f(x2) D.无法确定正确答案D