Set secondary school education Math suggestions

Set formulaSecondary school education learning point set formulation

* x€A  that means -x,A a material of set.
* x¢A  that means - x,A it's not material set.
* A<B  that means A,B  it's subsets.
* A>B that means A,B  exceeding set.
* {} Or ° blank set.
* U  universal set.
* AUB that means A and B conjunction set.
* A cabB that means AওB intersection set.
* A cabB= ° that means A and B Mutually intersection set.
* A\B=A-B that means A  watched set B pleasure set.
* A'=U-B that means A pleasure set.
* P(A) that means A power set
Note: € =belongs to element member of
           U= universal set
           U= union or cap
           Intersection= cap

                    ** Multiple formula**

If it any multiple 1st a, general ratios q so it?
1/ n expressions = aqn-1
2/ n expression of result Sn=a(qn-1)/q-1 [thenq>1]
                    Sn= a(1-qn)/1-q [ then q<1]
3/ eternal multiple expression  ,Sa= a/1-q
                   **Vassal**

Vassal expression 1st a, general  after word d ?
1/ n expression = a+(n-1)d
2/ n expression of result Sn =n/2{2a+(n-1)d}
3/ 1+2+3............…....+n=n( n+1)/2
4/ 1✓+2✓+3✓...........+n✓=n(n+1)(2n+1)/6
5/ 13+23....................+n3(n+1)✓/4
6/ a,b  =1/2 (a+b)
7/ 0/that means  = 0  that number /0 = a(uncountable)

               *Thanks*