单选题The symbol ☆ represents one of the fundamental arithmetic operators：+, -, ×, or ÷. If (x☆y)÷(y☆x)=1 for all positive values of x and y, then ☆ can represent ______.A + onlyB ÷onlyC + or × onlyD - or × onlyE +, -, ×, ÷

题目

单选题

The symbol ☆ represents one of the fundamental arithmetic operators：+, -, ×, or ÷. If (x☆y)÷(y☆x)=1 for all positive values of x and y, then ☆ can represent ______.

+ only

÷only

+ or × only

- or × only

+, -, ×, ÷

相似考题

1.In the following statements about functional dependency, which one is incorrect?A．Ifthen X→X'.B．If X→Y andthen X→Y'.C．If X→Y andthen X'→Y.D．If X→Y and Y→Z, then X→Z.

2.Which of the following indicate(s)possible values for the variables when the segment finishes execution?(74).Ⅰ. x=1,y=2Ⅱ. x=1,y=3Ⅲ. x=4, y=6A．ⅠB．Ⅰ,ⅡC．Ⅰ, ⅢD．ⅡandⅢ

3.以下程序运行后的输出结果是 ______。 Sub add(x，y) x=x+y Print "x="；x；"，y="；y End Sub Private Sub Command1_Click() x=1 y=1 Call add((x)，(y)) Print"x="; x；"，y="；y End SubA．x=1，y=1 x=2，y=2B．x=2，y=1 x=1，y=1C．x=1，y＝1 x=1，y=1D．x=2，y=1 x=2，y=1

4.In the following statements about functional dependency, which one is incorrect?A．If X→Y and Y→Z, then X→Z.B．If X→Y and, then X→Y'.C．If X→Y and, then X'→Y.D．If, then X→X'.

更多“单选题The symbol ☆ represents one of the fundamental arithmetic operators：+, -, ×, or ÷. If (x☆y)÷(y☆x)=1 for all positive values of x and y, then ☆ can represent ______.A + onlyB ÷onlyC + or × onlyD - or × onlyE +, -, ×, ÷”相关问题

第1题：

与y=(x>0? 1:x<0? －1:0);的功能相同的if语句是A.if(x>0)y=1 else if(x<0)y=－1; else y=O;B.i

与y=(x＞0? 1：x＜0? -1：0)；的功能相同的if语句是
A．if(x＞0)y=1 else if(x＜0)y=-1; else y=O；
B．if(x) if(x＞0)y=1； else if(x＜0)y=-1；
C．y=-1; if(x) if(x＞0)y=1； else if(x＝=0)y=0； else y=-1；
D．y=0； if(x＞=0) if(x＞0)y=1； else y=-1；

正确答案：A
解析：条件运算符要求有三个操作对象，它是c++语言中惟一的一个三目运算符。条件表达式的一般形式为：表达式1？表达式2：表达式3，先求解表达式1，若为非0(真)则求解表达式2，此时表达式2的值就作为整个条件表达式的值。若表达式1的值为0(假)，则求解表达式3，表达式3的值就是整个条件表达式的值。本题中用了两次三目运算符。
第2题：

已知y1(x)和y2(x)是方程y''+p(x)y'+Q(x)y=0的两个线性无关的特解， Y1(x)和Y2 (x)分别是方程y''+p(x)y'+Q(x)y=R1(x)和y''+p(x)y'+Q(x)y=R2(x)的特解。那么方程y''+p(x)y'+Q(x)y=R1(x)y+R2(x)的通解应是：
A. c1y1+c2y2B. c1Y1(x)+c2Y2(x)
C. c1y1+c2y2+Y1(x) D. c1y1+c2y2+Y1(x)+Y2(x)

答案：D
解析：
提示:按二阶线性非齐次方程通解的结构，写出对应二阶线性齐次方程的通解和非齐次方程的一个特解，得到非齐次方程的通解。
第3题：

public class X implements Runnable { private int x； private int y； public static void main（String [] args） { X that = new X（）；（new Thread（ that ））.start（）；（new Thread（ that ））.start（）； } public void run（） { for （；；） { synchronized （this） { x++； y++； } System.out.println（Thread.currentThread（）.getName（） + “x = “ + x + “， y = “ + y）； } } } What is the result？（）
- A、 Compilation fails.
- B、 The program prints pairs of values for x and y that might not always be the same on the same line （for example， “x = 2， y = 1”）.
- C、 The program prints pairs of values for x and y that are always the same on the same line （for example， “x = 1， y = 1”）. In addition， each value appears only once （for example， “x = 1， y = 1” followed by “x = 2， y = 2”）. The thread name at the start of the line shows that both threads are executing concurrently.
- D、 The program prints pairs of values for x and y that are always the same on the same line （for example， “x = 1， y = 1”）. In addition， each value appears only once （for example， “x = 1， y = 1” followed by “x = 2， y = 2”）. The thread name at the start of the line shows that only a single thread is actually executing.
正确答案:D
第4题：

public class X implements Runnable（ private int x； private int y； public static void main（Stringargs） X that = new X（）；（new Thread（that））.start（）；（new Thread（that））.start（）；） public void run（）（ for （；；）（ x++； y++； System.out.printIn（“x=” + x + “， y = ” + y）；）） What is the result？（）
- A、 Errors at lines 7 and 8 cause compilation to fail.
- B、 The program prints pairs of values for x and y that might not always be the same on the same line （for example， “x=2， y=1”）.
- C、 The program prints pairs of values for x and y that are always the same on the same line （for example， “x=1， y=1”. In addition， each value appears twice （for example， “x=1， y=1” followed by “x=1， y=1”）.
- D、 The program prints pairs of values for x and y that are always the same on the same line （for example， “x=1， y=1”. In addition， each value appears only for once （for example， “x=1， y=1” followed by “x=2， y=2”）.
正确答案:D
第5题：

单选题
public class X implements Runnable { private int x； private int y； public static void main（String [] args） { X that = new X（）；（new Thread（ that ））.start（）；（new Thread（ that ））.start（）； } public void run（） { for （；；） { synchronized （this） { x++； y++； } System.out.println（Thread.currentThread（）.getName（） + “x = “ + x + “， y = “ + y）； } } } What is the result？（）
A
Compilation fails.
B
The program prints pairs of values for x and y that might not always be the same on the same line （for example， “x = 2， y = 1”）.
C
The program prints pairs of values for x and y that are always the same on the same line （for example， “x = 1， y = 1”）. In addition， each value appears only once （for example， “x = 1， y = 1” followed by “x = 2， y = 2”）. The thread name at the start of the line shows that both threads are executing concurrently.
D
The program prints pairs of values for x and y that are always the same on the same line （for example， “x = 1， y = 1”）. In addition， each value appears only once （for example， “x = 1， y = 1” followed by “x = 2， y = 2”）. The thread name at the start of the line shows that only a single thread is actually executing.

正确答案： A
解析：暂无解析
第6题：

单选题
1. public class X implements Runnable（ 2. private int x； 3. private int y； 4. 5. public static void main（String[]args） 6. X that = new X（）； 7. （new Thread（that））.start（）； 8. （new Thread（that））.start（）； 9. ） 10. 11. public void run（）（ 12. for （；；）（ 13. x++； 14. y++； 15. System.out.printIn（“x=” + x + “， y = ” + y）； 16. ） 17. ） What is the result？（）
A
Errors at lines 7 and 8 cause compilation to fail.
B
The program prints pairs of values for x and y that might not always be the same on the same line （for example， “x=2， y=1”）.
C
The program prints pairs of values for x and y that are always the same on the same line （for example， “x=1， y=1”. In addition， each value appears twice （for example， “x=1， y=1” followed by “x=1， y=1”）.
D
The program prints pairs of values for x and y that are always the same on the same line （for example， “x=1， y=1”. In addition， each value appears only for once （for example， “x=1， y=1” followed by “x=2， y=2”）.

正确答案： C
解析：暂无解析
第7题：

单选题
If each of the equations below is graphed on the xy-plane, which one will produce a line with a positive slope containing the point (3, 2)?
A
x+y=5
B
x - y = 1
C
3x-2y = 10
D
x² -y=5
E
x +y² = 7

正确答案： A
解析：
因为直线方程式不包含带平方的项，如x²或y²，所以D和E不正确，因为它们不是直线。将点(3,2)代入到各个选项中，C项不符合。因为A项斜率为-1，不符合，故选B。
第8题：

单选题
If x and y are positive numbers greater than 1, and wx/y+w =1 then w= ______.
A
(x-1)/(y-1)
B
y/(x-1)
C
(x+1)/y
D
(x-y)/(x+y)
E
y/(x+1)

正确答案： A
解析：
因为wx/(y+w) =1，所以wx = y + w，则wx-w = y，w (x-1) = y，w = y/(x-1)，故选B。
第9题：

单选题
Let @ represent one of the four basic arithmetic operations such that, for any nonzero real numbers P and Q, P @ 0=P and P @ Q=Q @ P. Which arithmetic operation(S) does the symbol @ represent?
A
×only
B
+only
C
-only
D
-and×
E
+and÷

正确答案： A
解析：
If P @ Q=P, then symbol @ can represent either addition or subtraction, but not multiplication or division. Since it is also given that P @ Q=Q @ P, the operation @ is commutative. Since addition is commutative and subtraction is not commutative, the symbol @ represents only addition.
第10题：

单选题
public class X implements Runnable （ private int x； private int y； public static void main（String [] args）（ X that = new X（）；（new Thread（that）） . start（）；（new Thread（that）） . start（）；） public synchronized void run（）（ for （；；）（ x++； y++； System.out.printIn（“x = “ + x + “， y = “ + y）；））） What is the result？（）
A
An error at line 11 causes compilation to fail.
B
Errors at lines 7 and 8 cause compilation to fail.
C
The program prints pairs of values for x and y that might not always be the same on the same line （for example， “x=2， y=1”）
D
The program prints pairs of values for x and y that are always the same on the same line （for example， “x=1， y=1”. In addition， each value appears twice （for example， “x=1， y=1” followed by “x=1， y=1”）
E
The program prints pairs of values for x and y that are always the same on the same line （for example， “x=1， y=1”. In addition， each value appears twice （for example， “x=1， y=1” followed by “x=2s， y=2”）

正确答案： C
解析：暂无解析
第11题：

单选题
X= {1, 2, 4} Y= {1, 3, 4}12 If, in the sets above, x is any number in set X and y is any number in set Y, how many different values of x+y are possible?
A
Five
B
Six
C
Seven
D
Eight
E
Nine

正确答案： E
解析：
Given X = {1, 2, 4} and Y= {1, 3, 4}, make a list of all the possible sums x+y: 1+1=2; 2+1=3; 4+1=5; 1+3=4; 2+3=5; 4+3=7; 1+4=5; 2+4=6; 4+4=8 Hence, seven different values of x+y are possible: 2,3,4,5,6,7, and 8.
第12题：

问答题
What is the average (arithmetic mean) of x and y?　　(1) The average of x+3 and y+5 is 14.　　(2) The average of x,y and 16 is 12.

正确答案： D
解析：
将两条件分别代入计算可知，x和y的平均数均为10，故本题选D项。
第13题：

与y=(x>0?1:x<0?－1:0):的功能相同的if语句是()A.if(x>0)y=1; else if(x<0)y=－1; else y=0; else

与y＝(x＞0?1:x＜0?-1:0)：的功能相同的if语句是( )
A．if(x＞0)y=1； else if(x＜0)y=-1； else y＝0； else y=0；
B．if(x) if(x＞0)y＝1； else if(x＜0)y=-1；
C．y＝-1； if(x) if(x＞0)y＝1； else if(x==0)y＝0； else y=-1；
D．y＝0； if(x＞=0) if(x＞0)y=1； else y=-1：

正确答案：A
第14题：

1. public class X implements Runnable（ 2. private int x； 3. private int y； 4. 5. public static void main（String[]args） 6. X that = new X（）； 7. （new Thread（that））.start（）； 8. （new Thread（that））.start（）； 9. ） 10. 11. public void run（）（ 12. for （；；）（ 13. x++； 14. y++； 15. System.out.printIn（“x=” + x + “， y = ” + y）； 16. ） 17. ） What is the result？（）
- A、 Errors at lines 7 and 8 cause compilation to fail.
- B、 The program prints pairs of values for x and y that might not always be the same on the same line （for example， “x=2， y=1”）.
- C、 The program prints pairs of values for x and y that are always the same on the same line （for example， “x=1， y=1”. In addition， each value appears twice （for example， “x=1， y=1” followed by “x=1， y=1”）.
- D、 The program prints pairs of values for x and y that are always the same on the same line （for example， “x=1， y=1”. In addition， each value appears only for once （for example， “x=1， y=1” followed by “x=2， y=2”）.
正确答案:D
第15题：

public class X implements Runnable （ private int x； private int y； public static void main（String args）（ X that = new X（）；（new Thread（that）） . start（）；（new Thread（that）） . start（）；） public synchronized void run（）（ for （；；）（ x++； y++； System.out.printIn（“x = “ + x + “， y = “ + y）；））） What is the result？（）
- A、 An error at line 11 causes compilation to fail.
- B、 Errors at lines 7 and 8 cause compilation to fail.
- C、 The program prints pairs of values for x and y that might not always be the same on the same line （for example， “x=2， y=1”）
- D、 The program prints pairs of values for x and y that are always the same on the same line （forexample， “x=1， y=1”. In addition， each value appears twice （for example， “x=1， y=1” followed by “x=1， y=1”）
- E、 The program prints pairs of values for x and y that are always the same on the same line （for example， “x=1， y=1”. In addition， each value appears twice （for example， “x=1， y=1” followed by “x=2s， y=2”）
正确答案:E
第16题：

多选题
If x and y are both positive even integers, which of the following expressions must be even? (Select all such expressions.)
A
x^y
B
(x+1)^y
C
x^(y+1)

正确答案： B,A
解析：
由于题目中x和y是变量，可以根据题干给出的条件给x, y设定符合条件的数值，代入各选项，看结果是否符合题干要求，即可得出答案。
第17题：

单选题
For all real values of x and y, let x◆y be defined by the equation x◆y = 2 -xy. If -1 < a < 0 and 0 < b < 1, then which of the following must be true?
A
-2<a+b<-1
B
-l<a+b<0
C
0<a+b<l
D
l<a+b<2
E
2<a+b<3

正确答案： B
解析：
根据题干，发现a= -1/2, b =1/2满足已知条件，a◆b=2-ab，将a= -1/2, b =1/2代入进去，则(-1/2) ◆(1/2) = 2 - (-1/2)(1/2) = 2 + 1/4 = 2.25，故选E。
第18题：

单选题
public class X implements Runnable（ private int x； private int y； public static void main（Stringargs） X that = new X（）；（new Thread（that））.start（）；（new Thread（that））.start（）；） public void run（）（ for （；；）（ x++； y++； System.out.printIn（“x=” + x + “， y = ” + y）；）） What is the result？（）
A
Errors at lines 7 and 8 cause compilation to fail.
B
The program prints pairs of values for x and y that might not always be the same on the same line （for example， “x=2， y=1”）.
C
The program prints pairs of values for x and y that are always the same on the same line （for example， “x=1， y=1”. In addition， each value appears twice （for example， “x=1， y=1” followed by “x=1， y=1”）.
D
The program prints pairs of values for x and y that are always the same on the same line （for example， “x=1， y=1”. In addition， each value appears only for once （for example， “x=1， y=1” followed by “x=2， y=2”）.

正确答案： A
解析：暂无解析
第19题：

单选题
已知y1（x）与y2（x）是方程y″+P（x）y′+Q（x）y=0的两个线性无关的特解，Y1（x）和Y2（x）分别是是方程y″+P（x）y′+Q（x）y=R1（x）和y″+P（x）y′+Q（x）y=R2（x）的特解。那么方程y″+P（x）y′+Q（x）y=R1（x）+R2（x）的通解应是：（）
A
c1y1+c2y2
B
c1Y1（x）+c2Y2（x）
C
c1y1+c2y2+Y1（x）
D
c1y1+c2y2+Y1（x）+Y2（x）

正确答案： A
解析：暂无解析
第20题：

单选题
X = {-4,-2, 1,3}, Y= {-1,4,5}. If x is a number from set X, and y is a number from set Y. The probability that x + y is positive is closest to ______.
A
0.5
B
0.6
C
0.7
D
0.8
E
0.9

正确答案： B
解析：
Split the problem into four cases, one for each possible value of x. Then add each possible value of y (-1, 4, 5). x=-4, y=-5, 0, 1; x=-2, y=-3, 2, 3; x=1, y=0, 5, 6; x=3, y=2, 7, 8. There are 12 answers to (x + y). Eight of these are greater than 0. The probability that the sums of x and y are positive (greater than zero) is 8/12=0.66, which is closest to 0. 7.
第21题：

单选题
Phil has x quarters, y dimes, and z nickels and nothing else. Which of the following expressions represents the amount of money that Phil has, in dollars?
A
0.25x + 0.10y + 0.05z
B
2.5x + 1. 0y + 0.5z
C
25x + 10y + 5z
D
0.25x + 0.10y + 0.5z
E
25x + 10y + 50z

正确答案： B
解析：
Multiply the value of each coin by the number of coins and add. 0.25x + 0.10y + 0.05z.
第22题：

单选题
If 0>ab3c4, then which of the following must be true?Ⅰ. ab is positiveⅡ. ab is negativeⅢ. abc is negative
A
Ⅰ only
B
Ⅱ only
C
Ⅲ only
D
Ⅰ and Ⅲ only
E
Ⅱ and Ⅲ only

正确答案： D
解析：
Since ab³c⁴is negative and c⁴ is positive, then in ab³ one variable is positive and the other negative. Hence ab<0, or negative, so Ⅰ is false and Ⅱ is true. Now let’s look at Ⅲ. You know ab is negative — but you don’t know a thing about C. It could be positive or negative. So cross out E..
第23题：

单选题
x, y, and z are positive integers. Which of the following lists all the possible ways for x + y + z to be an odd number?I. One of the numbers is odd.II. Two of the numbers are odd.III. Three of the numbers are odd.
A
I
B
I and II
C
I and III
D
II and III

正确答案： C
解析：
I. One of the numbers is odd. Let x be odd. Let y and z be even. y + z is even. An even plus an odd is odd, so x + y + z is odd.

单选题The symbol ☆ represents one of the fundamental arithmetic operators：+, -, ×, or ÷. If (x☆y)÷(y☆x)=1 for all positive values of x and y, then ☆ can represent ______.A + onlyB ÷onlyC + or × onlyD - or × onlyE +, -, ×, ÷

题目

相似考题

更多“单选题The symbol ☆ represents one of the fundamental arithmetic operators：+, -, ×, or ÷. If (x☆y)÷(y☆x)=1 for all positive values of x and y, then ☆ can represent ______.A + onlyB ÷onlyC + or × onlyD - or × onlyE +, -, ×, ÷”相关问题

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