For loops and taylor series

I am having issued with my for loop taking the variable that i have set to be [1:1:n] but when i run my script it turns my answer into a scular in stead of a matrix.

here is what i have any help would be great thanks.

clc;
clear;
close all;

n = input('Please give number for the total number of terms in the taylor series: ');

x = input('Please give a value for "x": ');

approxValue = 0;  

% Initial value of approxValue.

for k = [0:1:n];

      approxVakue = (approxValue + k);

      approxValue = sum(x.^k/factorial(k));

% Gives the approx value of e^x as a taylor series
end

disp('approxValue =')

disp((approxValue))

disp('e^x =')

disp(exp(x))

[Dillan Masellas]

How can I perform this operation without using the power function?

Answer 1

[Matt Fig]

Use this loop instead:

for k = 0:n
    approxValue = (approxValue + x.^k/factorial(k));
    % Gives the approx value of e^x as a taylor series
end

I don't know what approxVakue is supposed to be doing in your code??

And what do you expect to be a matrix? Are you trying to save each term? If so:

approxValue = zeros(1,n+1);
for k = 0:n
    approxValue(k+1) = x.^k/factorial(k);
end

approxValuesum = sum(approxValue);  % Holds the estimate

This could also be done without FOR loops...

[SonOfAFather]

approxValue should be very close to the actual answer of e^x in the end when we use a large number of terms right now i am getting a huge differance in my answers.

Thank you that solved this freaking issue i am struggeling to learn this new language, Matlab, I find that i can do the computations, but knowing how to word it so that Matlab will accapt it is really kicking my butt. I can't thank you enough for you assistance.

[Matt Fig]

You're welcome!

[SonOfAFather]

i am still somewhatconfused as to why in the workspace the value of k is given as a number and not a vector? is it a result of the opperation be run and therefore at the end it is a number?

[Matt Fig]

k is the loop index. Thus k takes values of 0,1,...n one at a time, each time through the loop. Why would you need k at the end??

[SonOfAFather]

thank you i understand now. It wasn't that i needed to know that the value of k it was that it didn't do what i thought it would do. i thought that the value of k would still stay in vector form, but your explaination corrected my thought process. thank you.

[SonOfAFather]

In the end i was told that"n" should have been "n-1" in

for k = 0:n should have read k = 0:n.

the explaination i was given was that each time to loop processed through it needed to be one less.

thanks for you help. just thought i would tell you how i was corrected.