Epsilon-Delta continuity proof

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The discussion focuses on the Epsilon-Delta definition of continuity, specifically addressing the conditions for δ and the implications for x in the context of the function f(x) = x² + x + 3. The user seeks clarification on deriving δ < 1, the interval 0 < x < 2, and the inequality |x² + x + 3| < 9. It is established that δ is defined as the minimum of 1 and ε/9, ensuring δ < 1, which directly influences the permissible values of x.

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I'm trying to work through some examples, but I am not sure where the following comes from:



1. circled in black -- how do i get the δ<1?



2. circled in red -- how do I get 0<x<2, i.e. x∈(0,2)?



3. cirlced in blue -- how do i get |x^2+x+3|<9



Thanks, most appreciated.
 
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Let's start with 1 and 2.

delta is defined to be between 0 and min(1, epsilon/9).
min(x, y) means the minimum of x and y.
This means that delta < 1 and perhaps a lot smaller.

With delta < 1 and |x-1| < delta, what values can x take?
 

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