# Calculators Need help with TI-89 Titanium

1. May 19, 2007

### RaNe

Hi,

I'm working out some problems on my TI-89 Titanium, and I've run into a roadblock.

How do I put a base for a log?

Thanks a lot.

Last edited: May 20, 2007
2. May 20, 2007

### Xezlec

ln(thing you want the log of) / ln(base of the log)

As far as I know, that's the only way to do it on a TI. but it's not hard.

3. May 20, 2007

### z-component

That's the way I do it; just the standard log change of base formula. So ln(2) is just the log of 2, and ln(2)/ln(10) is log of 2, base 10. You can also see that ln(2)/ln(e), the base e log which is the natural log, will be just ln(2) since ln(e) evaluates to 1.

4. May 22, 2007

### Hymne

I borrow this thread a little if its okey..
I got a problem with mine TI-89.
Whay I want to calculate a root i press "diamond + 9 + x + , + y + enter" which should give me x^1/y. But all i get is what i just pressed, i.e. the answer i get is root(x,y).

5. May 22, 2007

### z-component

To find a root of x, use the zeros() function. Type zeros(expression,variable), or, alternatively, solve(equation,variable), when the equation is the same expression but set to zero, and the variable is x.

zeros(4x^2+3x+5,x) or solve(4x^2+3x+5=0,x) returns the roots.

6. May 22, 2007

### Hymne

Okey, but do you know where the problem for the root function could lie?
Could it be any setting?

EDIT: The problem was that I had changed languege... It now works again.

Last edited: May 23, 2007
7. May 24, 2007

### kevinf

another way to do log is to log(number, base)

8. May 25, 2007

### Xezlec

That doesn't work for me.

9. Jun 27, 2007

### Mk

I think he has one of those Apps like Omnicalc to upgrade the features kind of. That's also one way you can do it, just with a comma. Change of base requires a little more typing.

10. Apr 20, 2010

### morgans

if you press the yellow Diamond button and then press 7 then log will show up. much less typing for all you lazy people like me

11. Mar 10, 2011

### z01d

i.e. solve(log(x,8)=2/3,x)

x=4