[orgo814]

For finding an expansion coefficient I had an expression and evaluated δV/δT at 320 K to get the expression 3.9 x 10^-4/K + 2.96 x 10^-6 x 320/K. The answer is supposedly 1.34 x 10^-3/K and I'm obviously making some sort of math mistake because I'm not getting the answer when I evaluate that expression. I'm sure it's a simple math procedure but if someone could look at that equation and tell me how to get that answer that would be great. This is more a math question than a chemistry question!

[Dan]

I'm obviously making some sort of math mistake because I'm not getting the answer when I evaluate that expression.

Please show what you are doing, it is a forum rule.

[orgo814]

Well that's what I did.. I did the derivatives and got that expression beforehand. I tried solving the expression I gave you and couldn't figure out how they got that exact answer. I tried using order of operations which didn't give me it. I tried factoring out 1/K and didn't get it, etc. that was my reasoning.

[orgo814]

Disregard my question. Turns out my calculator was misfunctioning!

[curiouscat]

Disregard my question. Turns out my calculator was misfunctioning!

That's almost in league with "The dog ate my homework" 

...out of curiosity, what calculator do you use?

The closest I remember to this is that one old Intel chip that had a floating point bug.

[orgo814]

I had a ti 83 but I checked it with a ti 84 and got the answer I was supposed to get so in not sure what's wrong with my previous calculator or if its on some weird setting

[curiouscat]

I had a ti 83 but I checked it with a ti 84 and got the answer I was supposed to get so in not sure what's wrong with my previous calculator or if its on some weird setting

Probably you misinterpreting a syntax feature. Calculators can be idiosyncratic regarding parenthesis, binding order etc.

[Enthalpy]

I've had two pocket calculators (over 10) that did a mistake occasionnally. Using them hours a day for years, I finally knew under what computations sequences and values not to trust them. So it does exist - but is uncommon.

I also had one calculator that erased its user-tipped programmes and constants twice a year, but I couldn't determine under what conditions. For sure not my input.

Meanwhile I use a computer with Calcoo, which understands Polish notation and keyboard shortcuts.
Presently in Java, alas (but I still have an old one for Win):
http://calcoo.sourceforge.net/