Confusion on function handles
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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!
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답변 (2개)
Shashank Prasanna
2013년 9월 26일
편집: Shashank Prasanna
2013년 9월 26일
You need to precede your operations with a dot "." as described here:
http://www.mathworks.com/help/matlab/matlab_prog/array-vs-matrix-operations.html#btyv9yp-3 http://www.mathworks.com/help/matlab/ref/times.html
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
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
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))
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
2013년 9월 26일
Jesse commented
Azzi,
I take it I still need the dots to definte t(k)? How is t(k) defined? Thanks!
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