Example: "boxes approximately 20 kg in mass are allowed"
If your box is exactly 20 kg ... Will that be permitted or not?
It isn"t really clear.
You are watching: Upside down u symbol in math
Let"s see how to be specific about this in every of three popular methods:
Inequalities The Number heat Interval Notation
With Inequalities we use:
> greater than≥ greater than or same to less than≤ less than or same to
In "Interval Notation" we simply write the beginning and ending number of the interval, and use:
< > a square bracket when we desire to include
the finish value, or( ) a ring bracket as soon as we don"t
With the Number heat we attract a thick line to present the worths we room including, and:
a filled-in circle as soon as we want to encompass the end value, oran open up circle once we don"t
means every the numbers in between 0 and 20, perform not encompass 0, however do encompass 20
|From 1||To 2|
|Including 1||Not consisting of 1||Not including 2|| including 2|
|Inequality:||x ≥ 1 "greater than or same to"||x > 1 "greater than" ||x "less than" ||x ≤ 2 "less 보다 or equal to"|
|Number line:||1" width="70" height="55" />||, and not encompass 2:|
x ≥ 1 and x
or together: 1 ≤ x
That method up to and including $10.
And it is fair to say every prices are much more than $0.00.
As one inequality we display this as:
Price ≤ 10 and also Price > 0
In fact we could combine that into:
0 (0, 10>
Example: x higher than, or equal to, 3:
Example: x ≤ 2 or x >3
On the number line it looks like this:
And term notation looks choose this:
(-∞, 2> U (3, +∞)
We offered a "U" to typical Union (the joining together of 2 sets).
Note: be careful with inequalities like that one. Don"t try to join it into one inequality:
2 ≥ x > 3 wrong!
that doesn"t make sense (you can"t be less than 2 and greater 보다 3 at the same time).
Union and also Intersection
We simply saw exactly how to sign up with two sets making use of "Union" (and the prize ∪).
There is likewise "Intersection" which method "has to be in both". Think "where carry out they overlap?".
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The Intersection price is an upside under "U" prefer this: ∩
Example: (-∞, 6> ∩ (1, ∞)
The very first interval goes up to (and including) 6
The 2nd interval goes native (but no including) 1 onwards.
The Intersection (or overlap) of those 2 sets goes native 1 come 6 (not including 1, including 6):
Footnote: Geometry, Algebra and Sets
You might not have noticed this ... But we have actually been using: