Confusion on function handles

조회 수: 3 (최근 30일)
Jesse
Jesse 2013년 9월 26일
댓글: Shashank Prasanna 2013년 9월 27일
Greetings,
I know this is a tricky subject for me to understand, but I want to see if I'm going about this right.
I have the following three functions:
f(x)= x^8 + 8*x^7 + 28*x^6 + 56*x^5 +70*x^4 - 56*x^3 + 28*x^2 - 8*x +1
g(x)=(((((((x-8)*x + 28) - 56)*x + 70) - 56)*x + 28)*x - 8)*x + 1
h(x)=(x-1)^8
that need to be evaluated at 101 equally spaced points in the interval [0.99,1.01] and plot the results on the magnified scale.
Now, can I use function handles with this, i.e. (as a start),
f =@(x) x^8 + 8*x^7 + 28*x^6 + 56*x^5 +70*x^4 - 56*x^3 + 28*x^2 - 8*x +1
g =@(x) (((((((x-8)*x + 28) - 56)*x + 70) - 56)*x + 28)*x - 8)*x + 1
h =@(x) (x-1)^8
n = 100;
a = 0.99;
b = 1.01;
t = a:(b-a)/n:b;
Or am I way off?
Thanks!
  댓글 수: 1
Azzi Abdelmalek
Azzi Abdelmalek 2013년 9월 26일
Jesse, if you want to add a comment click on [comment on this answer]

댓글을 달려면 로그인하십시오.

답변 (2개)

Shashank Prasanna
Shashank Prasanna 2013년 9월 26일
편집: Shashank Prasanna 2013년 9월 26일
You need to precede your operations with a dot "." as described here:
Then create your anonymous function handles.
Create linearly spaced points using LINSPACE:
x = linspace(0.99,1.01,100);
Call the function with x as input
  댓글 수: 2
Azzi Abdelmalek
Azzi Abdelmalek 2013년 9월 26일
Jesse commented
Shashank,
Thanks for the response. Forgot about the dots! So, like this?
f =@(x) x.^8 + 8*x.^7 + 28*x.^6 + 56*x.^5 +70*x.^4 - 56*x.^3 + 28*x.^2 - 8*x +1 g =@(x) (((((((x-8)*x + 28) - 56)*x + 70) - 56)*x + 28)*x - 8)*x + 1 h =@(x) (x-1).^8
x = linspace(0.99,1.01,100);
Shouldn't the 100 be 101 for 101 equally spaced points?
So how is the call made in this fashion?
Thanks again!
Shashank Prasanna
Shashank Prasanna 2013년 9월 27일
Jesse, here is an example, you can follow the same approach for any anonymous function handles that has been defined the proper way to do elementwise operations:
h =@(x) (x-1).^8;
x = linspace(0.99,1.01,100);
plot(x,h(x))

댓글을 달려면 로그인하십시오.


Azzi Abdelmalek
Azzi Abdelmalek 2013년 9월 26일
for k=1:numel(t)
y(k)=f(t(k))+g(t(k))+h(t(k))
end
plot(t,y)
  댓글 수: 1
Azzi Abdelmalek
Azzi Abdelmalek 2013년 9월 26일
Jesse commented
Azzi,
I take it I still need the dots to definte t(k)? How is t(k) defined? Thanks!

댓글을 달려면 로그인하십시오.

카테고리

Help CenterFile Exchange에서 Adding custom doc에 대해 자세히 알아보기

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by