# Calculators Integral program for TI-84?

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1. Jun 21, 2010

### think4432

I don't know if this is the right place to post a question like this...but help?

Does anyone know of a good program that can be downloaded to a ti84 that can solve integrals? It doesn't have to show the steps...just an answer [that you could check while doing homework...if you don't have access to internet to get on WolframAlpha and check the problem?]

2. Jun 22, 2010

### think4432

3. Jun 25, 2010

### Santa1

Symbolic? The TI-84 has en extremely limited processor and very little memory, I doubt that exists.

It has a built in numerical function called fnInt which you could use to compare answers with.

4. Jun 25, 2010

### think4432

What does the fnInt function do? And where can I find it?

5. Jun 29, 2010

### Santa1

It's at MATH, 9.

The syntax is
Code (Text):
fnInt(f(vars), var, lower, upper)
with an additional optional argument of accuracy (
Code (Text):
fnInt(f(vars), var, lower, upper, accuracy)
).

So two uses would be
Code (Text):
fnInt(sin(x), x, 0, 1)
and
Code (Text):
fnInt(x^12/(e^x+1), x, 0, 230, 1E-16)
.

However for checking integrals you can plot the function you suspect is the correct answer together with the integrand look for obvious errors and check some key points with differentiation (2nd CALC, 6). Obviously this method has several faults so be extremely cautious of what points you choose and which x range you plot. This method will only accurately tell you if have the wrong integral (within the calculators numerical bounds), but if you are cautious enough can also give you an idea if you have the right answer or not.