Q2 of 31 Page 1

Find the tenth term of the sequence √2, √8, √18, ………

Given sequence,


√2, √8, √18, …


The above can be re-written as:


√2, 2√2, 3√2, …


Let us find the differences between terms


a2 – a1 = 2√2 – √2 = √2


a3 – a2 = 3√2 – 2√2 = √2


As the differences between terms are same, the above sequence is an AP with


First term, a = √2


Common difference, d = √2


We know,


nth term of an AP, an = a + (n – 1)d


As we have to find 10th term, n = 10


Putting the values, we get


a10 = √2 + (10 – 1)√2


= 10√2


= √200


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