How can I get decimal answers on my TI-89 calculator when using pi?

[Ryuk1990]

This is not necessarily a math question, but I have a problem with a TI-89 calculator. Calculating something with pi doesn't give me a decimal answer. For example, if I put in 2*pi, it will just give an answer of 2pi instead of 6.28. How do I fix this?

 

[robert Ihnot]

It frequently does that sort of thing, preferring things like 3/5, for example. Unfortunately I have been told not to just give away answers, so I can only say that you have to study the manual. One reason the calculator does that is to avoid the error of round off.

However, besides a certain button, just like with PARI--a free download--you can sometimes get around such things by writing 2(pi)x1.0, and trying that.

 

[red apple]

Two solutions as far as I can remember. I think there is a setting in modes for decimal or exact and settings, you could switch that.

Or if you press the green button (the one with the dot) it will give answers in decimal if you are in exact mode, and exact answers if you are in decimal mode.