Can someone help me with this assignment?

i'm using MatLab grader

[Rik]

Have a read here (or here for more general advice) and here. It will greatly improve your chances of getting an answer. You can find guidelines for posting homework on this forum here.

[Maryam AlKhoury]

fa=@(x) (2.*x.^3+3.*x.^2-6.*x+19)./(7.*x.^3-20.*x-5);  % define the function for part (a)-REMEMBER to use element-by-element operations (.*  ./  .^)
x=[-10 -100 -1000 -10000 -100000 -1000000 -10000000]; % define the vector x
ya=f(x)  % calculate f(x) (No semicolon to see output)
syms x; % DO NOT CHANGE CODE ON THIS LINE
aLimit=limit( )  % No semicolon

% Repeat the above process for part (b)
fb=@(x) sqrt(4.*x.^2+7.*x+1)-2.*x; 
x=[10 100 1000 10000 100000 1000000 10000000];
yb=f(x) 
syms x;
bLimit=limit( )

this is my code... i dont know how to choose the values of x and what to write in "ya= "

Answer 1

[madhan ravi]

fa=@(x) (2.*x.^3+3.*x.^2-6.*x+19)./(7.*x.^3-20.*x-5);  % define the function for part (a)-REMEMBER to use element-by-element operations (.*  ./  .^)
x=[-10 -100 -1000 -10000 -100000 -1000000 -10000000]; % define the vector x
ya=fa(x)  % calculate f(x) (No semicolon to see output)
syms x; % DO NOT CHANGE CODE ON THIS LINE
aLimit=limit((2.*x.^3+3.*x.^2-6.*x+19)./(7.*x.^3-20.*x-5),x,-inf )  % No semicolon
% Repeat the above process for part (b)
fb=@(x) sqrt(4.*x.^2+7.*x+1)-2.*x; 
x=[10 100 1000 10000 100000 1000000 10000000];
yb=fb(x) 
syms x;
bLimit=limit(  sqrt(4.*x.^2+7.*x+1)-2.*x,x,inf)

command window:

>> COMMUNITY
ya =

    0.2382    0.2814    0.2853    0.2857    0.2857    0.2857    0.2857

 
aLimit =
 
2/7
 

yb =

    1.7025    1.7449    1.7495    1.7499    1.7500    1.7500    1.7500

 
bLimit =
 
7/4
 
>> 

[madhan ravi]

Read about limit() it's not that difficult to imply in MATLAB

[Rik]

@Madhan, congratulations for reaching the 2k rep level, especially in such a short time.

[madhan ravi]

@Rik thank you very much :)

[Maryam AlKhoury]

it says that there's an error at line 3 ya=f(x)

[madhan ravi]

Try

clear all %at the very beginning

and try again

I got the result!

[madhan ravi]

see edited answer

[Maryam AlKhoury]

i tried that but i still get the same error

[madhan ravi]

upload the code that you are trying , did you try my answer ?

[Maryam AlKhoury]

i tried substituting values for ya and yb and this is what i got

[madhan ravi]

i edited my answer please try again

[Maryam AlKhoury]

i got the same answer as you but for some reason i got this error:

[madhan ravi]

please upload the code that you are trying becausse you should be getting any error

[Maryam AlKhoury]

fa=@(x) (2.*x.^3+3.*x.^2-6.*x+19)./(7.*x.^3-20.*x-5) ;  % define the function for part (a)-REMEMBER to use element-by-element operations (.*  ./  .^)
x=[-10 -100 -1000 -10000 -100000 -1000000 -10000000]; % define the vector x
ya=fa(x)  % calculate f(x) (No semicolon to see output)
syms x; % DO NOT CHANGE CODE ON THIS LINE
aLimit=limit((2.*x.^3+3.*x.^2-6.*x+19)./(7.*x.^3-20.*x-5),x,-inf)  % No semicolon

% Repeat the above process for part (b)
fb=@(x) sqrt(4.*x.^2+7.*x+1)-2.*x; 
x=[10 100 1000 10000 100000 1000000 10000000];
yb=fb(x)
syms x;
bLimit=limit(sqrt(4.*x.^2+7.*x+1)-2.*x,x,inf)

[Maryam AlKhoury]

and this is my output:

ya =

0.2382 0.2814 0.2853 0.2857 0.2857

aLimit =

2/7

yb =

1.7025 1.7449 1.7495 1.7499 1.7500

bLimit =

7/4

[madhan ravi]

This is my output when i tried your answer , your getting error because you should be getting 7 elements but instead your are getting 5

>> COMMUNITY
ya =
    0.2382    0.2814    0.2853    0.2857    0.2857    0.2857    0.2857
 
aLimit =
 
2/7
 
yb =
    1.7025    1.7449    1.7495    1.7499    1.7500    1.7500    1.7500
 
bLimit =
 
7/4
 
>> 

[madhan ravi]

or try

format longg

at the very beginning of your code

[Maryam AlKhoury]

this is my output (7 elements) but i still get an error:

ya =

0.2382 0.2814 0.2853 0.2857 0.2857 0.2857 0.2857

aLimit =

2/7

yb =

1.7025 1.7449 1.7495 1.7499 1.7500 1.7500 1.7500

bLimit =

7/4

[madhan ravi]

You have met all the requirements but why is it showing an error?

[Maryam AlKhoury]

yeah i dont know

[madhan ravi]

Better ask your teacher maybe he has set an unique algorithm ?

[Maryam AlKhoury]

yeah okay.. thanks anyways for your help

[madhan ravi]

Glad could help upto a certain , not satisfied though