# Meaning of x:x < 9

• September 29th 2011, 11:03 AM
FailInMaths
Meaning of x:x < 9
Actually it's C={x:x < 9}, does that mean x is lesser than 9 ?

Thanks
• September 29th 2011, 11:11 AM
Chris L T521
Re: Meaning of x:x < 9
Quote:

Originally Posted by FailInMaths
Actually it's C={x:x < 9}, does that mean x is lesser than 9 ?

Thanks

Yes, you're right. $C=\{x:x<9\}$ is the set theoretic way of saying the interval $(-\infty,9)$.
• September 29th 2011, 11:17 AM
FailInMaths
Re: Meaning of x:x < 9
Quote:

Originally Posted by Chris L T521
Yes, you're right. $C=\{x:x<9\}$ is the set theoretic way of saying the interval $(-\infty,9)$.

Thanks ! (Nod)