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प्रश्न
Can 2n2 – 7 be the nth term of an A.P.? Explain.
उत्तर
We have 2n2 – 7,
Substitute n = 1, 2, 3, …, we get
2(1)2 – 7, 2(2)2 – 7, 2(3)2 – 7, 2(4)2 – 7, ….
–5, 1, 11, ….
Difference between the first and second term = 1 – (–5) = 6
And difference between the second and third term = 11 – 1 = 10
Here, the common difference is not same.
Therefore, the nth term of an A.P. can't be 2n2 – 7.
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