is it true or false is so it is false 
 
        
             
        
        
        
Answer:
discriminant = b * b - 4 * a * c
discriminant = b ** 2 - 4 * a * c
Explanation:
The operands are correct and in the right order (for python).
** is the operand for squaring something.
* is the operand for multiplying something.
- is the operand for subtracting something.
 
        
                    
             
        
        
        
Answer:
- import java.util.Arrays;
- public class Main {
- 
-     public static void main(String[] args) {
-         String [] first = {"David", "Mike", "Katie", "Lucy"};
-         String [] middle = {"A", "B", "C", "D"};
-         String [] names = makeNames(first, middle);
- 
-         System.out.println(Arrays.toString(names));
-     }
- 
-     public static String [] makeNames(String [] array1, String [] array2){
- 
-            if(array1.length == 0){
-                return array1;
-            }
- 
-            if(array2.length == 0){
-                return array2;
-            }
- 
-            String [] newNames = new String[array1.length];
- 
-            for(int i=0; i < array1.length; i++){
-                newNames[i] = array1[i] + " " + array2[i];
-            }
- 
-            return newNames;
-     }
- }
Explanation:
The solution code is written in Java. 
Firstly, create the makeNames method by following the method signature as required by the question (Line 12). Check if any one the input string array is with size 0, return the another string array (Line 14 - 20). Else, create a string array, newNames (Line 22). Use a for loop to repeatedly concatenate the string from array1 with a single space " " and followed with the string from array2 and set it as item of the newNames array (Line 24-26). Lastly, return the newNames array (Line 28).
In the main program create two string array, first and middle, and pass the two arrays to the makeNames methods as arguments (Line 5-6). The returned array is assigned to names array (Line 7). Display the names array to terminal (Line 9) and we shall get the sample output: [David A, Mike B, Katie C, Lucy D]
 
        
             
        
        
        
Answer:
def sum_1k(M):
    s = 0
    for k in range(1, M+1):
        s = s + 1.0/k
    return s
def test_sum_1k():
    expected_value = 1.0+1.0/2+1.0/3
    computed_value = sum_1k(3)
    if expected_value == computed_value:
        print("Test is successful")
    else:
        print("Test is NOT successful")
test_sum_1k()
Explanation:
It seems the hidden part is a summation (sigma) notation that goes from 1 to M with 1/k.
- Inside the <em>sum_1k(M)</em>, iterate from 1 to M and calculate-return the sum of the expression.
- Inside the <em>test_sum_1k(),</em> calculate the <em>expected_value,</em> refers to the value that is calculated by hand and <em>computed_value,</em> refers to the value that is the result of the <em>sum_1k(3). </em>Then, compare the values and print the appropriate message
- Call the <em>test_sum_1k()</em> to see the result