From trigonometry we know that: 
if 
then,  (where
 (where  is an integer)
 is an integer)
This can be rewritten in degrees as:
 .............(Equation 1)
.............(Equation 1)
Now, in our case, 
Therefore, (Equation 1) can be written as:
 ..........(Equation 2)
..........(Equation 2)
Now, to find the correct options all that we have to do is replace n by relevant integers and find the values of  that match.
 that match.
For n=2, (Equation 2) gives us:  .
.
Thus, 
Now, we know that: 
Let n=-1, then:

Thus, 
Likewise, 
Only the last option  will never match
 will never match  because no integral value of
 because no integral value of  will ever give
 will ever give 
Thus the last option is the correct option.
 
        
                    
             
        
        
        
Answer:
1  1/4
Step-by-step explanation:
3 1/8 - 1 7/8
I like to line them up vertically
 3 1/8
- 1 7/8
---------------
We need to borrow from the 3
Take 1 from the 3 and make it 8/8
  2 (1/8+8/8)
- 1 (7/8)
--------------------- 
 2 (9/8)
- 1 (7/8)
--------------------- 
1  2/8
Simplify the fraction by dividing by 2 on the top and bottom
1 1/4
 
        
             
        
        
        
Answer:
Total number of ways to select all sstudent to make assignment = 10×36×70×1 = 25200
Step-by-step explanation:
We have given number of students = 10
These 10 students are assigned to four dorm rooms a single, a double, a triple and a quad 
So number of ways to assigned single student 
Now left student = 10 -1 = 9
So number of ways to assigned double student 
Now left student = 9-2 = 7
So number of ways to assigned triple student  =70
=70
Now left student = 7 - 3 = 4
So number of ways to assigned quad student 
So total number of ways to select all sstudent to make assignment = 10×36×70×1 = 25200
 
        
             
        
        
        
Answer:
(1/4)³
Step-by-step explanation:
Hope it helps you