<p>I think you are suppose to use l'hopitals rule for this but im not sure. Regardless, I got 0 as the answer.</p>
<p>[(2x+5)/(2x)]^(-x/3)
lim
x-----> infinity</p>
<p>Are you sure you copied it right? By graphing it, it resolves to 2173 / 5000, but I don’t think people do that by hand.</p>
<p>nope, thats the exact problem</p>
<p>LOL Nevermind</p>
<p>i got infinity for the answer.</p>
<p>Easy. Split the fraction.</p>
<p>1 + 5/2x</p>
<p>Or, 1 + 2.5/x.</p>
<p>There’s a cute little identity that says </p>
<p>lim x–> infinity of </p>
<p>(1 + a/x )^(bx) = e^(ab)</p>
<p>We have</p>
<p>(1 + 2.5/x)^(-(1/3)x).</p>
<p>a = 2.5, b = -1/3</p>
<p>thus</p>
<p>The answer is e^(-2.5/3) or e^(-5/6)</p>
<p>We’re supposed to know L’Hopital’s rule for AB??? </p>
<p>WE saw a question like that and our teacher just said to ignore it, it’s not AB. </p>
<p>Ahh?</p>
<p>Unfortunately, you don’t need the super special awesome L’Hopital’s Rule for this problem.</p>
<p>It’s not like it’s a hard rule to grasp either. Nothing beyond AB for sure.</p>
<p>Yeah, that’s how to solve it, but questions like that don’t show up on the ab exam.</p>