SOLUTION: If the sum of the first n terms of an AP is 4n-n square,what is the first term. What is the first two terms,second term.

SOLUTION: If the sum of the first n terms of an AP is 4n-n square,what is the first term. What is the first two terms,second term.

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Question 972742: If the sum of the first n terms of an AP is 4n-n square,what is the first term. What is the first two terms,second term.
Answer by amarjeeth123(570) (Show Source): You can put this solution on YOUR website!
sum of the first n terms of an AP is 4n-n square=n(4-n)=(n/2)(8-2n)=(n/2)[6+(n-1)(-2)]
sum of the first n terms of an AP=(n/2)[2a+(n-1)d]
Comparing both we get a=3 and d=-2
First term a1=3
Second term a2=a+d=3-2=1
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