# I can't figure out how to define X in a piecewise function to create a Bending Moment Diagram

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Ezekiel Lawrence on 20 Sep 2021
Commented: Ezekiel Lawrence on 20 Sep 2021
I missed this lecture and am trying to figure it out so it doesn't bite me going forward.
My professor supplied us with this script which is supposed to display the M(x) piecewise, "momentfunctionarray.mlx" which reads as follows:
function y = momentfunctionarray(x)
len = length(x);
for i = 1:1:len
if x(i) >= 0 && x(i) < 3
y(i) = 265*x(i)-5.56*x(i)^3;
elseif x(i) >= 3 && x(i) < 6
y(i) = -50*x(i)^2 + 415*x(i) - 150;
elseif x(i) >= 6 && x(i) < 10
y(i) = -185*x(i) + 1650;
elseif x(i) >= 10 && x(i) <= 12
y(i) = 100*x(i) - 1200;
end
end
My problem is I don't know how to build the function that defines "x" for step 1 so that the piecewise can be useful.

Sargondjani on 20 Sep 2021
The script of your professor is actually the function. Save it and you can call the function.
function handle:
myfun = @(x)momentfunctionarray(x)
but there is really no point in doing this.
You can for example evaluate a function with argument x as follows:
x=linspace(0:0.01:20);
y = myfun(x);
You should look into the example of fplot and fzero to find out how to get those things.
Ezekiel Lawrence on 20 Sep 2021
I see now, Thank you greatly, and I will go review fplot and fzero.

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