SOLUTION: The first term of an arithmetical progression is 11 and the sums of the first five and the first ten terms respectively are equal in magnitude but different in sign.Find the second
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Question 909311: The first term of an arithmetical progression is 11 and the sums of the first five and the first ten terms respectively are equal in magnitude but different in sign.Find the second term of the progression. Answer by mananth(16946) (Show Source):
You can put this solution on YOUR website! The first term of an arithmetical progression is 11 and the sums of the first five and the first ten terms respectively are equal in magnitude but different in sign.Find the second term of the progression.
a=11
S5 =-S10
sum of n terms
Sn = n/2(2a+(n-1)d)
S5 =5/2(2*11+(5-1)d)
=5/2(22+4d)
=5(11+2d)
