Exercise 4.2.5. Use Definition 4.2.1 to supply a proof for the following limit statements. (a) $\lim_{x \to 2} (3x + 4) = 10$. (b) $\lim_{x \to 0} x^3 = 0$. (c) $\lim_{x \to 2} (x^2 + x - 1) = 5$. (d) $\lim_{x \to 3} \frac{1}{x} = \frac{1}{3}$.
Added by Sean H.
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Let's start by manipulating the expression |(-2x+4) - 10| < ε: |-2x+4 - 10| < ε |-2x - 6| < ε |2(x + 3)| < ε 2|x + 3| < ε Now, we can see that if we choose δ = ε/2, then for any 0 < |x - a| < δ, we have: |2(x + 3)| < 2δ = 2(ε/2) = ε Show more…
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a. $\lim _{x \rightarrow 4^{+}} \frac{x-5}{(x-4)^{2}}$ b. $\lim _{x \rightarrow 4^{-}} \frac{x-5}{(x-4)^{2}} \quad$ c. $\lim _{x \rightarrow 4} \frac{x-5}{(x-4)^{2}}$
Limits
Infinite Limits
Determining limits analytically Determine the following limits or state that they do not exist. a. $\lim _{x \rightarrow 4^{+}} \frac{x-5}{(x-4)^{2}}$ b. $\lim _{x \rightarrow 4^{-}} \frac{x-5}{(x-4)^{2}} \quad$ c. $\lim _{x \rightarrow 4} \frac{x-5}{(x-4)^{2}}$
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