Gh. Soleimani
- 48
- 1
4. Let consider A as set of a new type of Arithmetic Progression where:
a1 = x, d1 = S, d2 = L and a1, d1, d2, nϵ N then:
A = {(a1 = x), (a2 = a1+S), (a3 = a2+L),(a4 = a3+S), (a5 = a4+L)…(an = a(n -1)+S or L)}
In fact, we have common difference d1 and d2 which are added periodically to generate the members of set A.Rule 4: If n = 2k +1, k ≥ 0 then an = x + {(n-1)/2}(S +L) and
If n = 2k, k ≥ 0 then an = x + 0.5 {(n-2)L + nS}
Rule 5: Sn = (x*n) + {(S * (n^2)) / 4} + {(L * ((n^2) – 2n)) / 4)
A general form for Sn is:
Sn = (x*n) + {((aS*S) + (aL*L)) / 4}
Where: aS = (n^2) - (n mod 2)
And aL = ((n-1) ^2) - ((n+1) mod 2)
Example 1: Assume a1 = 1, d1 = 3, d2 = 4 , k = 2 and n = 5 then we have:
A = {1, 4, 8, 11, 15}
n = 2k + 1= 5, an = 1 + ((5-1)/2)*(3+4) = 15
aS = (5^2) – 1= 24 , aL = ((5-1)^2) – 0 = 16
Sn = (1*5) + (((24*3) + (16*4))/4) = 39
Example 2: Assume a1 = 3, d1 = 5, d2 = 9, k = 3 and n = 6 then we have:
A = {3, 8, 17, 22, 31, 36}
n = 2k = 6, an = 3 + 0.5*(((6-2)*9) + (6*5)) = 36
aS = (6^2) – 0= 36 , aL = ((6-1)^2) – 1 = 24
Sn = (3*6) + (((36*5) + (24*9))/4) = 117
a1 = x, d1 = S, d2 = L and a1, d1, d2, nϵ N then:
A = {(a1 = x), (a2 = a1+S), (a3 = a2+L),(a4 = a3+S), (a5 = a4+L)…(an = a(n -1)+S or L)}
In fact, we have common difference d1 and d2 which are added periodically to generate the members of set A.Rule 4: If n = 2k +1, k ≥ 0 then an = x + {(n-1)/2}(S +L) and
If n = 2k, k ≥ 0 then an = x + 0.5 {(n-2)L + nS}
Rule 5: Sn = (x*n) + {(S * (n^2)) / 4} + {(L * ((n^2) – 2n)) / 4)
A general form for Sn is:
Sn = (x*n) + {((aS*S) + (aL*L)) / 4}
Where: aS = (n^2) - (n mod 2)
And aL = ((n-1) ^2) - ((n+1) mod 2)
Example 1: Assume a1 = 1, d1 = 3, d2 = 4 , k = 2 and n = 5 then we have:
A = {1, 4, 8, 11, 15}
n = 2k + 1= 5, an = 1 + ((5-1)/2)*(3+4) = 15
aS = (5^2) – 1= 24 , aL = ((5-1)^2) – 0 = 16
Sn = (1*5) + (((24*3) + (16*4))/4) = 39
Example 2: Assume a1 = 3, d1 = 5, d2 = 9, k = 3 and n = 6 then we have:
A = {3, 8, 17, 22, 31, 36}
n = 2k = 6, an = 3 + 0.5*(((6-2)*9) + (6*5)) = 36
aS = (6^2) – 0= 36 , aL = ((6-1)^2) – 1 = 24
Sn = (3*6) + (((36*5) + (24*9))/4) = 117