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Re: sum of exponentials
Posted:
Nov 24, 2012 12:28 PM


"dwi" wrote in message <k8qlsv$ktj$1@newscl01ah.mathworks.com>... > Ok, I understand now how this works. But still, you said the result will be > x(3)+x(2)*e^(1)+x(1)*e^(2))/(1+e^(1)+e^(2)); > while I want > (x(3)*e^(1)+x(2)*e^(2)+x(1)*e^(3))/(e^(1)+e^(2)+e^(3)); > Also, how would your code change if I had e^(1/20), e^(2/20), e^(3/20) etc?         The two expressions
(x(3)*e^(1)+x(2)*e^(2)+x(1)*e^(3))/(e^(1)+e^(2)+e^(3))
and
(x(3)+x(2)*e^(1)+x(1)*e^(2))/(1+e^(1)+e^(2))
are identically equal. Just divide the numerator and denominator of the first expression by e^(1) to get the second expression. What you want and what this code produces are the same thing.
As to your second question, just the two lines
a = x(k) + a*f*e^(1); b = 1 + b*f*e^(1);
would need to be changed to:
a = x(k) + a*f*e^(1/20); b = 1 + b*f*e^(1/20);
Roger Stafford



