# Calculators TI-89 Calculator

1. Oct 20, 2004

### TSN79

I'm having some trouble solving inequalities with the TI-89. Let's say that I want to solve $$x^2<1$$ The answer should be $$<-1,1>$$, if I type in solve(x^2<1,x), but that's not what I get. It only returns the inequality itself just as I typed in. What's wrong??

2. Oct 20, 2004

### Tom McCurdy

i will have to check the set up but if its all entered correctly make sure you clear your varables so you don't have x stored as something

3. Oct 20, 2004

### aeroegnr

I don't think that the TI-89 will solve inequality equations. You'll have to separate the inequality into two separate equations and solve them separately.

If the TI-89 does have this function, I am unaware. Just checking my manual it doesn't look like it.

4. Dec 31, 2008

### vaikunth2004

TI 89 is pretty complicated. I had a similar problem and a Person I know that works a t Texas Instrument Company that makes calculators claims it doesn't do inequalities and is a ripoff for what it seems. aerognr is right.good Luck though!!!:)

5. Dec 31, 2008

### gunch

This is quite surprising to me because I have a TI-89 Titanium and it can easily solve inequalities. Writing your original query I got: -1<x<1. I was under the impression that the CAS was identical, but apparently they upgraded it.

6. Jan 1, 2009

### deiki

try :

solve(sign(factor(x^2-1))=-1,x)