# How to check dy/dx in my ti84?

1. Oct 2, 2009

### Impackt

1. The problem statement, all variables and given/known data
find dy/dx: y=4sinx-5cosx+x

2. Relevant equations

3. The attempt at a solution
y=4sinx-5cosx+x

I know this may look simple, but i want to learn how to check my answers in my ti84 to be sure that I'm correct.

2. Oct 2, 2009

### n!kofeyn

The TI-84 can't take derivatives. Only the TI-89 or Voyage 200 calculators can do that, since they're the only ones that carry TI's computer algebra software. Casio and HP also make calculators that can do this.

3. Oct 2, 2009

4. Oct 2, 2009

### n!kofeyn

Those will be highly unreliable and will only handle special cases. The TI-84 is only able to numerically differentiate a function. To my knowledge, it can only graph some derivatives and spit out the value of the derivative at a specific point.

I recommend using Wolfram Alpha. For example, to take the derivative of the function you gave, you would have the following http://www.wolframalpha.com/input/?i=d/dx+(4*sin(x)-5*cos(x)+x)".

Last edited by a moderator: Apr 24, 2017
5. Oct 2, 2009

### Impackt

Thanks for linking me to that site! I can use it to help me study :surprised

Last edited by a moderator: Apr 24, 2017