Help! Something wrong with my Ti-84+!?

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1

<p>I'm trying to do this integral:
<a href="http://s4.photobucket.com/albums/y141/djAZUL/ti83problemintegral.jpg%5B/url%5D"&gt;http://s4.photobucket.com/albums/y141/djAZUL/ti83problemintegral.jpg&lt;/a>
However, when I type it into Y1 and try to do the integral I get this message:
ERR: INVALID
1: QUIT
2: GOTO</p>

<p>If I choose "GOTO" I get taken back to a graph of the function and the selector is blinking on the upper limit (it is blinking on 113.4, as if something is wrong with this upper limit). I can integrate from 0 to 10 just fine, but any upper limit that is greater than 10 results in this error. What's the problem?</p>

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<p>I think you have to change your window so you can see your upper bound. Make you window span from -10 to 120 on the X axis and try it</p>

3

<p>tanman - Yup, I tried changing the window and it works now. Thanks!</p>

4

<p>The answer I got is 142898.9454. That seems like a really crazy answer, but this integral is pretty crazy so that's understandable. XD</p>

<p>If that answer is right, here's how to plug it in:
fnInt((30e^-0.3x),X,0,113.4)</p>

<p>I hope this helps! :) Good luck!</p>

<p>**EDIT: **tanman beat me to it XD I didn't realize you were doing the integral by the area under the curve, but if you were doing it by Math > 9, the above method should work.</p>

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<p>Lotus Blossom - The answer is 966.69341. It is -.03, not -.3, by the way (I'm still not sure how you got that huge answer though...).</p>

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<p>Oh XD Thanks for pointing that out, Azure. :)</p>

<p>Now when I plug it into fnInt I get 187,192.5385...any idea what I might be doing wrong? This is how I plugged it in this time:
fnInt((30e^-0.03x),X,0,113,4)</p>

<p>Oh goodness gracious. For some reason I've been having trouble properly typing these buggers in lately >__o</p>

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<p>fnInt(30e^(-.03x),X,0,113.4)</p>

<p>That's what mine reads, and it gets me 966.6934099.</p>

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<p>Lotus, make sure you enter 113.4, not 113,4. If you used a comma, the function is probably calculating the integral from 0 to 113 with a tolerance of 4 (vs a normal tolerance of 10^-5)</p>