Isolate a variable on TI-89 titanium

[RickiG]

Hi

I been fiddeling around with a rather large equation to isolate a variable.
Now it seems to be right.. can I check this with my newly purchased Ti-89 titanium?

Simple example.

If I have x+y = z
can I get Ti-89 to give me x = z-y

Meaning, can I specify a variable and have Ti-89 isolate it for me?

Thanks for any help given, I cant seem to find any in the manual, but I am quite sure I heard that Ti-89 can do this.
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[rockvee]

you can use solve() function to do it (in algebra menu), put the equation first, then a comma, the the varible you want to isolate. in your example, it would be: solve(x+y=z,x) and it will return you x=z-y. Similarly, if you want isolate y, put: solve(x+y=z,y) and it will return you y=z-x

[RickiG]

Thank you!

I had tried with solve(f(x)) but I had made the mistake of having values instead of variables in my formula and Ti-89, being a very smart calculator, tried it´s best to give me an answer ... when I took out all the values in my formula and put in variables instead it gave me the right formula.

If anyone else should be reading this...

I found out that Ti-89 will put in a '@' as a constant when there might be more than one solution to the equation .. ie. sometimes both x and -x will make the equation true...this, and other tricks Ti-89 do to include all solutions, can seriously make a simple equation look really scary.

I my case I was calculating frequencies and these can not be negative so I got a much better answer doing this.

solve(x+y=z,y | y > 0) (meaning: AND y is greater than zero .. weird since '|' normally means OR..)

This makes ti-89 only look at the positive solutions for this equation.

Thanks again
_________________
Fix it! fix it! Fix it! fix it! Fix it! fix it! Fix it! fix it! Fix it! fix it!.....