I understand that the limit of sec^2(x) as x approaches pi/2 is infinity (increasing without bound), and I understand the meaning of this in terms of the epsilon-delta definition of an infinite limit.(adsbygoogle = window.adsbygoogle || []).push({});

I also understand why the limit of sec(x) as x approaches pi/2 doesn't exist.

What I'm a bit "sketchy" on is why my calculator (Ti-89 Titanium) displayes "infinity" as the value for sec^2(pi/2) and "undefined" for sec(pi/2) (not when evaluating the limit, but just when evaluating the function at that value). Why aren't sec^2(pi/2) and sec(pi/2) both displayed as "undefined"? Neither sec^2(x) nor sec(x) have a defined value at pi/2, do they? The fact that in one case the limit exists doesn't seem to have any effect on the value of either functionpi/2 (my book stresses the point that the limit of f(x) as x->a doesn't necessarily mean that f(a) = L, f(a) need not even exist -- which seems to be the case here)at

I'm also confused because there is a bit of ambiguity in my mind concerning "1/0" and "infinity"

Can anyone help me understand this...?

-GeoMike-

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# Limits, infinity, and my calculator

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