# How to solve a function with different ranges

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Delia Bosshart on 15 Jun 2021
Edited: Scott MacKenzie on 15 Jun 2021
I have a variable that is composed of two functions for different ranges:
alfa_ox = 1/15*C_ox for 0 <= C_ox <= 15
alfa_ox = 1 for C_ox > 15
When I imply this in Matlab, it doesnt consider the second condition (that alfa can't be bigger than 1). How can I solve that?
C_ox = [16;15;7.5;2;7.5;15;15];
if C_ox > 15
alfa = 1
else alfa = 1/15.*C_02
end
Output:
alfa =
1.0667
1.0000
0.5000
0.1333
0.5000
1.0000
1.0000
Scott MacKenzie on 15 Jun 2021
Sorry for the string of comments here, but your question uses the expression
1/15*C_ox
1/15.*C_02

Star Strider on 15 Jun 2021
alfa_fcn = @(C_ox) min(C_ox/15,1);
C_ox = [16;15;7.5;2;7.5;15;15];
alfa = alfa_fcn(C_ox)
alfa = 7×1
1.0000 1.0000 0.5000 0.1333 0.5000 1.0000 1.0000
.
Delia Bosshart on 15 Jun 2021
Thank you!

Alan Stevens on 15 Jun 2021
Try
C_ox = [16;15;7.5;2;7.5;15;15];
C_ox(C_ox<=15)=C_ox(C_ox<=15)/15;
C_ox(C_ox>15)=1
C_ox = 7×1
1.0000 1.0000 0.5000 0.1333 0.5000 1.0000 1.0000