a function just valid over a certain range

Hello everyone, let me ask

a formula is expressed mathematically as follows

Y = x^2 + 3x + 1 , for 2<x<8;

Y = 0 for else (x<2 or x>8)

then I would plot Y value for Y within 0<x<10.

in excel I succeeded by writing the following formula

=IF(AND(x >= 2, x<=8), x^2+3x+1, 0)

with similar logic, I write this in Matlab

x = 0:0.1:10 ;

if 2 <= x <= 8

y = x.^2+3.*x+1 ;

else

y = 0

end

plot(x,y)

please see the graph above, which for the value of Y at x < 2 is not 0

[Stephen23]

The simple MATLAB approach is to use logical indexing:

x = 0:0.1:10;
y = x.^2+3.*x+1;
y(x<2 | x>8) = 0; 
plot(x,y)

Answer 1

[VBBV]

  x = 0:0.1:10 ;
for k  = 1:length(x)
      if x(k) >= 2 & x(k)<= 8
       y(k) = x(k).^2+3.*x(k)+1 ;
      else
       y(k) = 0;
      end
end 
plot(x,y)

[VBBV]

Use the logical condition to check for values lying between 2 and 8 as below

if x(k) >= 2 & x(k)<= 8

[Satriyo]

Thanks for your answer.

Best Regards,