From trigonometry we know that:
if
then, (where
is an integer)
This can be rewritten in degrees as:
.............(Equation 1)
Now, in our case,
Therefore, (Equation 1) can be written as:
..........(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.
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
because no integral value of
will ever give
Thus the last option is the correct option.