Does this help:
Let 1 - 1/x2 = -1 and solve for x to get the limiting values of x at the -1 level
.
First be aware that x cannot equal 0
Next muliply everything by x squared
can you do it from there?
Hi 315
it's after 3am here and I'm on my phone so my full answer will have to wait till morning. Sorry :)
Let's take this in "pieces"
We have
-1 ≤ 1 - 1/x^2 subtract 1 from both sides
-2 ≤ -1/x^2 multiply both sides by -1 and reverse the inequality sign
2 ≥ 1/x^2 rearrange
x^2 ≥ 1/2 subtract 1/2 from both sides
x^2 - 1/2 ≥ 0 factor
(x - 1/√2) (x + 1/√2) ≥ 0
And we have two possible intervals that work, here
(-∞, -1/√2] and [1/√2, ∞)
Now, let's look at the other piece
1 - 1/x^2 ≤ 1 subtract 1 from both sides
-1/x^2 ≤ 0 divide by -1 on both sides and reverse the sign
1/x^2 ≥ 0
And the possible intervals here are
(-∞, 0), (0, ∞)
But, we have to take the most "restrictive" intervals that would make the original inequality true
Notice that the interval (-1/√2, 1/√2) makes the original inequality untrue
So, the intervals that "work" are (-∞, -1/√2] and [1/√2, ∞)