以下（）正确定义了接口。 A: interfaceInterfaceB{ voidprint(){}; } B: abstractinterfaceInterfaceB{<br> voidprint(); } C: InterfaceA1,InterfaceA2是已经定义的接口 interfaceInterfaceBextendsInterfaceA1,InterfaceA2 voidprint(){}; } D: interfaceInterfaceB{<br> viodprint(); }

interfaceA{doublef(doublex,doubley);}classBimplementsA{publicdoublef(doublex,doubley){returnx*y;}intg(inta,intb){returna+b;}}publicclassE{publicstaticvoidmain(Stringargs&#91;&#93;){Aa=newB();System.out.println(a.f(3,5));//【代码1】Bb=(B)a;System.out.println(b.g(3,5));//【代码2】}}代码1输出()代码2输出()

以下（） 接口的定义是正确的。 A: interfaceA{voidprint(){};} B: abstractinterfaceB{voidprint(){};} C: abstractinterfaceCextendsA,B{abstractvoidprint(){};} D: interfaceD{voidprint();}

下列程序段运行结果是()interfaceA{doublef(doublex,doubley);}classBimplementsA{publicdoublef(doublex,doubley){returnx*y;}intg(inta,intb){returna+b;}}publicclassE{publicstaticvoidmain(String&#91;&#93;args){Aa=newB();System.out.println(a.f(3,5));Bb=(B)a;System.out.println(b.g(3,5));}} A: 15.0,8.0 B: 15.08 C: 158 D: 815

以下的类(接口)定义中正确的是( ) A: public class A{ private int x; public getX(){ return x; }} B: public abstract class A{ private int x; public abstract int getX(); public int aMethod(){ return 0; }} C: public class A{ private int x; public abstract int getX();} D: public interface interfaceA{ private int x; public int getX(){ return x; }}

【单选题】NO 2 、NO 2 - 、NO 2 + 键角大小关系正确的是 。 A. NO 2 > NO 2 - >NO 2 + B. NO 2 + >NO 2 >NO 2 - C. NO 2 - > NO 2 >NO 2 + D. NO 2 + > NO 2 - >NO 2

求定积分[img=179x43]17da65388c0b1ca.png[/img]； （ ） A: log(2^(1/2) + 1)/2 + 2^(1/2)/2 B: log(2^(1/2) + 1)/2 - 2^(1/2)/2 - 1/2 C: log(2^(1/2) + 1)/2 + 2^(1/2)/2 - 1/2 D: log(2^(1/2) + 1)/2 + 2^(1/2)/2 + 1/2

2 + 2 * (2 * 2 - 2) % 2 / 3

函数z=xsiny在点(1,π/4)处的两个偏导数分别为 A: √2/2,√2/2 B: √2/2,-√2/2 C: -√2/2,-√2/2 D: -√2/2,√2/2

2×2×2×2×2