what is one possible value of x for which x < 2 < 1/x ?
is a possible value for x because
Inverting and multiplying that last expression,
or
and that is true!
Other possible values of x would be ,,, etc.
How did I get that?
Greater than zero means "positive"
Less than zero means "negative"
We try Case 1: (which means x is a positive number)
We multiply through the right inequality by positive number x
and the inequality sign does not reverse:
Since x is a positive number in this case, and the product
is negative, and since a positive number must
be multiplied by a negative number in order to get a negative
number, then must be a negative number, so
In order for a positive number to be both less than 2
and also less than , it needs to be less
than
So therefore:
We try Case 2: (which means x is a negative number)
If we multiply the second inequality by x, which in this case is
negative, we reverse the inequality symbols:
Since x is a negative number in this case, and the product
is negative, and since a negative number must
be multiplied by a positive number in order to get a negative
number, then must be a positive number. But then
implies with contradicts .
So Case 2 is impossible.
We try Case 3: x = 0
This is impossible since would not be defined.
Therefore only Case 1 is possible, so the solution is
and the solution set is
So x can be any positive value between 0 and , exclusive of
. x could be any fraction whose numerator is less than half
its denominator. Or x could be any decimal whose tenths digit is less \
than 5, such as .437 or .33339, etc.
Edwin