Creating an equation with multiple inputs.

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Alexander
Alexander on 12 Nov 2013
Answered: Walter Roberson on 12 Nov 2013
I'm trying to make an equation where I put in three variables and get an answer. This is what I have so far. Every time I try to run it, it says "undefined function or variable 't.'"
line(t,A_0,a);
N(t) = exp^(A_0/a)*(1-exp^-at);
line(4,3,5);

Answers (2)

Image Analyst
Image Analyst on 12 Nov 2013
As you have used it, t needs to be an index - an integer like 1, 2, 3, 4, etc. Or it can be a logical vector if you've previously defined N.
The way you've used line(), t, A_0, and a must be arrays, not scalars, so in that case you must use dots in your equations to process all elements of the array:
N(t) = exp^(A_0 ./ a) .* (1-exp(-a .* t));
and I don't understand your second call to line - it doesn't make sense.
  2 Comments
Alexander
Alexander on 12 Nov 2013
the second call line was the numbers I was trying to plug in for each variable. I did what you said, but it's still giving me the same error.
Image Analyst
Image Analyst on 12 Nov 2013
Look up line() in the help to see how it should be used.
It's hard to debug a program when most of it is missing, particularly the code before the three lines that you snipped out.

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Walter Roberson
Walter Roberson on 12 Nov 2013
My guess is that you want
function N = line(t,A_0,a)
N = exp^(A_0./a).*(1-exp.^(-a.*t));
end

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