Summation with looping

Find ∑((x^)n/n!) for x=1.8 and n=0 to 16.

Okay, my first attempt to do this looked like:

x = 1.8 For(0:16) xs = sum((x^n)/factorial(n)) end

xs

But I received the error: ??? Error: File: imageanalystbs.m Line: 11 Column: 6 Unexpected MATLAB expression.

My line 11 is the one with "For (0:16)"

What am I doing wrong here? Any help is appreciated.

Answer 1

[Paulo Silva]

for n=0:16 is the correct syntax, you are also making another error by doing the summation in every iteration, you should instead find all values and do the summation after the loop ends

x = 1.8
xl=zeros(17,1);                 %preallocation of the storage
for n=0:16
xl(n+1) = ((x^n)/factorial(n)); %save every iteration result
end
xs=sum(xl)                      %calculate the sum of the iteration results

it can also be done without loops

n=0:16;
xs = sum(((x.^n)./factorial(n))); %notice the dots

[Sean de Wolski]

Ah - faster fingers!

[Paulo Silva]

Hi Sean!

[Sean de Wolski]

Hey Paulo, welcome back!

[Paulo Silva]

Nice to be here again, congratulations for your new job, they couldn't choose a better man :)

[Daniel]

Thank you Paulo! I will give it a try and see what happens. No worries Sean, you were a great help on the last question. :)

[OLUBUKOLA ogunsola]

i hope someone will still answer this after a long time. how can i achieve this without the built in function factorial, also ill like x to vary from say , 1 to 1000?

Answer 2

[Image Analyst]

I think the problem is in your filename:

"imageanalystbs.m"

That sounds like a horrible name to me.

ImageAnalyst

[Daniel]

Sorry, I don't see a problem?

[Salah Saad]

he's being sarcastic...ish, it still is a weird filename