Contact Us!
CoCalc Logo Icon
StoreFeaturesDocsShareSupportNewsAboutSign UpSign In

Real-time collaboration for Jupyter Notebooks, Linux Terminals, LaTeX, VS Code, R IDE, and more,
all in one place. Commercial Alternative to JupyterHub.

| Download
Views: 89
Image: ubuntu2204
Kernel: SageMath 10.0

Limits Assignment

Note:

You'll see comments below on Questions 1 through 3 stating, "The limit is approximately." Type a number at the end of this line to indicate your answer.

If the (two-sided) limit does not exist, write DNE.

Question 1

[2 points] Consider limx2x2x6x36x2+32\displaystyle\lim_{x\to-2}\frac{x^2-x-6}{x^3-6x^2+32}.

Caution: It's a little hard to see, but this limit is at 2-2.

Part a

Estimate the limit to two decimal places by zooming in on a graph.

(-2) == (-2)^3 - 6(-2)^2 + 32(-2)^2 - (-2) - 6
--------------------------------------------------------------------------- TypeError Traceback (most recent call last) Cell In [4], line 1 ----> 1 (-Integer(2)) == (-Integer(2))**Integer(3) - Integer(6)(-Integer(2))**Integer(2) + Integer(32)(-Integer(2))**Integer(2) - (-Integer(2)) - Integer(6) TypeError: 'sage.rings.integer.Integer' object is not callable
#The limit is approximately:92

Part b

Estimate the limit numerically from the left using at least seven values.

#The limit is approximately:

Part c

Estimate the limit numerically from the right using at least seven values.

#The limit is approximately:

Part d

Compute the limit using CoCalc's limit command. [Convert your answer to a decimal in order to compare it with the results above.]

Question 2

[2 points] Consider limx1x31x1\displaystyle\lim_{x\to1}\frac{x^3-1}{\sqrt{x}-1}.

Part a

Estimate the limit to two decimal places by zooming in on a graph.

#The limit is approximately:

Part b

Estimate the limit numerically from the left using at least seven values.

#The limit is approximately:

Part c

Estimate the limit numerically from the right using at least seven values.

#The limit is approximately:

Part d

Compute the limit using CoCalc's limit command.

Question 3

[2 points] Consider limx0x(x+2)x\displaystyle\lim_{x\to0}\frac{x\cdot (x+2)}{|x|}.

Note: To get x|x|, use abs(x) in CoCalc.

Part a

Estimate the limit to two decimal places by zooming in on a graph.

plot((x* (x+2) ) /abs (x) , xmin=-.1, xmax=.1)
Image in a Jupyter notebook
#The limit is approximately:DNE

Part b

Estimate the limit numerically from the left using at least seven values.

var('x') f(x) = (x* (x+2) )/abs(x) f(-.1)
-1.90000000000000
var('x') f (x) = (x* (x+2) )/abs (x) f(- .1)
-1.90000000000000

#The limit is approximately: -1.99

Part c

Estimate the limit numerically from the right using at least seven values.

var('x') f(x) = (x* (x+2) ) /abs (x) f(.1)
2.10000000000000
var('x') f(x) = (x* (x+2) ) /abs (x) f(.01)
2.01000000000000
#The limit is approximately: 2.00

Part d

Compute the limit using CoCalc's limit command.

var ('x') f(x)=(x* (x+2)) / (abs (x)) limit(f(x),x=0)
und

Question 4

[1 point] Let f(x)=x24x21\displaystyle f(x)=\frac{x^2-4}{x^2-1}.

Part a

Use CoCalc's limit command to compute the right limit limx1+f(x)\displaystyle\lim_{x\to1^+}f(x).

var('x') f(x) = (x^2-4) /(x^2-1) limit (f(x),x=1,dir="right")
-Infinity

Part b

Use CoCalc's limit command to compute the left limit limx1f(x)\displaystyle\lim_{x\to1^-}f(x).

[Careful: This is not the limit as x approaches 1-1. This is the limit as x approaches positive 11 from the left.]

var('x') f(x) = (x^2-4) / (x^2-1) limit(f(x),x=1,dir= 'left')
+Infinity

Question 5

[2 points] Consider the function f(x)=4x29x4x1\displaystyle f(x)=\frac{\sqrt{4x^2-9x}}{4x-1}.

Part a

Compute limxf(x)\displaystyle\lim_{x\to-\infty}f(x).

var('x') f(x)=sqrt(4*x^2-9*x)/(4*x-1) limit(f(x),x=-infinity)
-1/2

Part b

Compute limxf(x)\displaystyle\lim_{x\to\infty}f(x).

var('x') f(x) =sqrt (4*x^ 2-9*x) /(4*x-1) limit(f(x),x=+infinity)
1/2

Part c

Graph f(x)f(x) using xmin= -100, xmax=100, ymin= -1, ymax=1.

Recall, if either of the limits above is a number, then the graph of ff has a horizontal asymptote. Does your graph have two horizontal asymptotes that match the answers from parts a and b?

plot(sqrt(4*x^2-9*x)/(4*x-1), xmin=-100,xmax=100, ymin=-1, ymax=1)
Image in a Jupyter notebook

Question 6

[1 point] Let f(x)=2x+4f(x)=\sqrt{2x+4}. Compute limbaf(b)f(a)ba\displaystyle\lim_{b\to a}\frac{f(b)-f(a)}{b-a}.

[Don't forget to declare variables a and b.]

var('x,a,b') f(x)=sqrt(2*x+4) limit ((f(b)-f (a))/(b-a), b=a)
1/sqrt(2*a + 4)
1