how to write an equation with different period of time
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how can I writ this equation in matlab.
25*t 0<= t <= 2
W(t)= 50 2<= t <= 4
-05t+250 4<= t <=5
thank for everyone trying to help.
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Answers (3)
Tomas
on 3 Feb 2014
Edited: Tomas
on 3 Feb 2014
I can think of two ways, one is using a "for" and ifs and its not very efficient but it will get it done like this:
t=0:0.1:5
for i=1:length(t)
if t(i)>=0 &&t(i)<=2
w(i)=25*t;
elseif t>=2 && t<=4
w(i)=50;
elseif t>=5 && t<=5
w(i)=-5*t+250;
end
end
The other one is harder to explain. I hope this is enough.
Walter Roberson
on 3 Feb 2014
w = nan(size(t));
idx = 0 <= t & t= < 2;
w(idx) = t(idx) * 25;
idx = 2 <= t & t <= 4;
w(idx) = 50;
idx = 4 <= t & t <= 5;
w(idx) = 250 - 50 * t;
Notice that this leaves undefined (NaN) any position for which t < 0 or t > 5.
You double-define the values at 2 exactly and 4 exactly but the two definitions have the same value at the exact boundary so there is no discontinuity.
4 Comments
Walter Roberson
on 4 Feb 2014
Edited: per isakson
on 17 Sep 2017
function r = w(t)
r = nan(size(t));
idx = 0 <= t & t= < 2;
r(idx) = t(idx) * 25;
idx = 2 <= t & t <= 4;
r(idx) = 50;
idx = 4 <= t & t <= 5;
r(idx) = 250 - 50 * t;
end
The above defines an equation named "w" that takes a parameter on input and returns the value according to your definition.
This is what you asked, to define the equation.
You can use the equation like any MATLAB function, by calling its name and passing in the value you want to process. For example,
T = -10:.01:10;
plot(T, w(T))
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