find the sum of nth term of ap whose kth term is 5k+1
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Answered by
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We know that nth term of an AP = a + (n - 1) * d.
Given kth term of an AP ak = 5k + 1.
Substitute k = 1, we get
= > a1 = 5(1) + 1
= 6.
= > a2 = 5(2) + 1
= 11.
Common difference d = a2 - a1
= > 11 - 6
= > 5.
Now,
We know that sum of n terms of an AP sn = (n/2)[2a + (n - 1) * d]
= > (n/2)[2(6) + (n - 1) * 5]
= > (n/2)[12 + 5n - 5]
= > (n/2)[5n + 7].
Hope this helps!
siddhartharao77:
:-)
Answered by
0
Step-by-step explanation:
step 1 -Find a and d
step2 -put values of a and d in Sn
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