Base of the exponential equation should be (-1).
And finally the product or result should also be a negative number.
Let us take a variable for n natural numbers.
(Note: All positive whole numbers are called natural numbers that is 1,2,3,4,5,....).
In order to get the expression, we need to find the expession for odd natural numbers.
We know,
The expession for odd natural numbers is given by = 2n-1.
Where n= 1,2,3,4,5...
If we have an odd exponent of a negative number, it always gives a negative number.
We got, base = -1 ( a negative number) and
exponent = (2n-1) ........... expression for odd number.
Therefore, we could write final exponential expression that would give a negative for all natural numbers.