# Calculators Sinc function on TI-89

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1. Sep 21, 2009

### tenacity2986

how to graph sinc function on ti-84

sinc(x) = sin(pi X) / pi X

solution:

sinc(x) = sin(pi X) / (pi X)

yes it was that simple!

Last edited: Sep 21, 2009
2. Sep 21, 2009

### Staff: Mentor

Can you graph sin(pi X)? That would be a good start. And then...

3. Sep 21, 2009

### vk6kro

You would have to read the book that came with the calculator.

But if you just wanted to see a graph of the right hand side of the equation try Wolfram Alpha:
http://www57.wolframalpha.com/input/?i=sin(pi+X)+/(+pi+X)

4. Sep 21, 2009

### tenacity2986

its not that it doesnt graph the function, but it graphs it backwards or something. From 0, it oscilllates with higher and higher amplitude to infinity and to negative infinity.

The highest oscillation is suppose to be at 1 when x=0 and oscillate down from x=0 to zero at x= infinity.

5. Sep 21, 2009

### waht

check the x and y axis

6. Sep 21, 2009

### vk6kro

Have a look at the graph on Wolfram Alpha. It does oscillate with decreasing amplitude as you describe.

I had to bracket the Pi X bit to ( Pi X) to get it accepting the X on the bottom line. Maybe your calculator is doing the same thing. Bringing the X to the top would give a rising amplitude.

I just graphed the right hand side of the equation, otherwise it gave very peculiar squiggly lines. Try just graphing the right hand side of the equation.

7. Sep 21, 2009

### tenacity2986

thankyouu veryy much to everyone for encouraging a solution in our communityyy here!! i hope to give back to your questions in the same way you've helped me... It was a super trivial solution which when dividing by pi*x, i had to put parenthesis!!! duhhh!! and u would think a senior in EE would know how to use his calculatorr!! LOL

8. Sep 21, 2009

### Staff: Mentor

Knowing your calculator's subtleties for input is one thing. Knowing how to use a keyboard is another...

Glad we were able to help.