TI-89 Differentiation: How to Get Algebraic Derivative and Why Negative Result?

[Helicobacter]

1. After I launch the "Home" program and enter

d(x^2,x)

The calculator spits out -52.4916, a numerical solution. What I want is the algebraic derivative 2x - how do I get to the algebraic derivative?

2. When I enter sin(60), it gives me -0.304811 as an output. Why does the Ti-89 give a negative result, while the Ti-83 provides me with a positive one?

Sorry if I'm in the wrong forum. The forum search didn't spit out anything.

 

[chroot]

1. Make sure you don't have x defined as some constant. If you just enter 'x,' what does it return?

2. Make sure the calculator is set for degrees, not radians.

- Warren

 

[Helicobacter]

1. Make sure you don't have x defined as some constant. If you just enter 'x,' what does it return?

2. Make sure the calculator is set for degrees, not radians.

- Warren

Thank you for your feedback, Warren. You are right, I associated a number with x. How can I make it a variable again?

 

[d_leet]

Thank you for your feedback, Warren. You are right, I associated a number with x. How can I make it a variable again?

I think there's a menu option, I think second then f1, or maybe f5 will give you the option to clear a-z or maybe it's under the var-link think which would be second then "-". The batteries in my 89 are dead so I can't check which one it is, but I'm pretty sure it's one of those.

 

[Jameson]

I have my TI-89 right here, so I'll look. Yep, go to VAR-LINK and scroll down until you see stored items and you should see "x" there. Delete it and you're good!