a) Let \( \epsilon=1 / 2 \). Show that no possible \( \delta>0 \) satisfies the following condition: For all \( x, 0<|x-1|<\delta \quad \Longrightarrow \quad|f(x)-2|<1 / 2 \). That is, for each \( \delta>0 \) show that there is a value of \( x \) such that \[ 0<|x-1|<\delta \quad \text { and } \quad|f(x)-2| \geq 1 / 2 . \] This will show that \( \lim _{x \rightarrow 1} f(x) \neq 2 \). b) Show that \( \lim _{x \rightarrow 1} f(x) \neq 1 \). c) Show that \( \lim _{x \rightarrow 1} f(x) \neq 1.5 \).
Added by Kristi A.
Close
Step 1
### Part a) Show that \( \lim _{x \rightarrow 1} f(x) \neq 2 \) ** Show more…
Show all steps
Your feedback will help us improve your experience
Harsha M and 90 other Calculus 1 / AB educators are ready to help you.
Ask a new question
Labs
Want to see this concept in action?
Explore this concept interactively to see how it behaves as you change inputs.
Key Concepts
Recommended Videos
Consider $\lim _{x \rightarrow 2} \frac{1}{x}$ (a) Show that if $|x-2|<1,$ then $$ \left|\frac{1}{x}-\frac{1}{2}\right|<\frac{1}{2}|x-2| $$ (b) Let $\delta$ be the smaller of 1 and 2$\epsilon .$ Prove the following: $$\text If\quad 0 < |x-2| < \delta, \quad \text { then }\left|\frac{1}{x}-\frac{1}{2}\right| < \epsilon $$ (c) Find a $\delta>0$ such that if $0<|x-2|<\delta,$ then $\left|\frac{1}{x}-\frac{1}{2}\right|<0.01$ (d) Prove rigorously that $\lim _{x \rightarrow 2} \frac{1}{x}=\frac{1}{2}$
LIMITS
The Formal Definition of a Limit
Let $f(x)=\frac{x}{|x|} .$ Prove rigorously that $\lim _{x \rightarrow 0} f(x)$ does not exist. Hint: Show that for any $L,$ there always exists some $x$ such that $|x|<\delta$ but $|f(x)-L| \geq \frac{1}{2},$ no matter how small $\delta$ is taken.
The Formal Definition of a Limit Preparing for the AP Exam
Show that if $\lim _{x \rightarrow 0} f(x)=L$. then $\lim _{x \rightarrow 0} f(a x)=L$ for each $a \neq 0$ HINT: Let $\epsilon > 0 .$ If $\delta_{1} > 0$ "works" for the first limit, then $\delta=\delta_{1} /|a|{\text {"works" for the second limit. }}$
Limits and Continuity
The Pinching Theorem; Trigonometric Limit
Recommended Textbooks
Calculus: Early Transcendentals
Thomas Calculus
Watch the video solution with this free unlock.
EMAIL
PASSWORD