Limits

Epsilon and Delta Revisited

Some time ago we looked at the meaning of the definition of limits, and I included several links to additional discussions on the subject. Now I want to took at three of those, which fit together rather nicely. We’ll look deeply into the proof that the limit of \(x^2\), as x approaches 2, is 4, …

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Limit of sin(x)/x

Last week we looked at some recent questions about limits, where we focused first on what limits are, in terms of graphs or tables, and then on finding them by algebraic simplification. This week, we’ll look at two old questions about a trigonometric limit that can’t be determined that way: sin(x)/x, as x approaches zero.

Separable Differential Equations

(A new question of the week) We received a couple different questions recently about solving differential equations by separation of variables, and why the method is valid. We’ll start with a direct question about it, and then look at an attempt at an alternate perspective using differentials.