3p (p + 1)
If the sum of p terms of a series is
4
the series is an......
Answers
Answer:
60
Step-by-step explanation:
= 3p(p+1)
= 3*4 (4+1)
= 12 * 5
= 60
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Answer :
Option (1) : A.P.
Note :
★ A.P. (Arithmetic Progression) : A sequence in which the difference between the consecutive terms are equal is said to be in A.P.
★ If a1 , a2 , a3 , . . . , an are in AP , then
a2 - a1 = a3 - a2 = a4 - a3 = . . .
★ The common difference of an AP is given by ; d = a(n) - a(n-1) .
★ The nth term of an AP is given by ;
a(n) = a1 + (n - 1)d .
★ If a , b , c are in AP , then 2b = a + c .
★ The sum of nth terms of an AP is given by ; S(n) = (n/2)×[ 2a + (n - 1)d ] .
★ The nth term of an AP can be also given by ; a(n) = S(n) - S(n-1) .
★ A linear polynomial in variable n always represents the nth term of an AP .
★ A quadratic polynomial in variable n always represents the sum of n terms of an AP .
Solution :
Here ,
The given expression for sum of p terms of a series is ;
=> S(p) = 3p(p + 1)/4
=> S(p) = 3(p² + p)/4
=> S(p) = 3p²/4 + 3p/4
Clearly ,
The polynomial S(p) is quadratic .
Thus ,
S(p) must represents the sum of p terms of an AP series .