DIRECTION : In the following questions, a statement of assertion (A) ...
We have, common difference of an AP
d =an - an - 1 is independent of n or constant.
So, A is correct but R is incorrect.
View all questions of this test
DIRECTION : In the following questions, a statement of assertion (A) ...
Algorithm
Step I. Obtain an
Step II. Replace n by (n - 1) is an to get an-1
Step III. Calculate an− an-1
Step IV. Check the value of an− an-1 .
If an− an-1 is independent of n, then the given
sequence is an A.P. Otherwise it is not an A.P
suppose an= 3-4n
put n=n-1
an-1=3-4(n-1)=3-4n+4
an-an-1=3-4n-3+4n-4 =-4 ( independent of n) so A is false.
common difference must be the same so it must be independent from 'n'
d=2n (never be considered because in this case d not remain the same)
Hence correct option is D
DIRECTION : In the following questions, a statement of assertion (A) ...
Assertion (A): an - an-1 is not independent of n then the given sequence is an AP.
Reason (R): Common difference d = an - an-1 is constant or independent of n.
The correct answer is option 'D': Assertion (A) is false but reason (R) is true.
Explanation:
To determine whether the given sequence is an Arithmetic Progression (AP) or not, we need to consider the definition of an AP.
An Arithmetic Progression (AP) is a sequence in which the difference between any two consecutive terms is constant.
In other words, if the sequence follows the pattern a, a + d, a + 2d, a + 3d, ..., where 'a' is the first term and 'd' is the common difference, then it is an AP.
Now let's analyze the given assertion and reason:
Assertion (A): an - an-1 is not independent of n then the given sequence is an AP.
This assertion is not always true. The difference between any two consecutive terms, an - an-1, can vary with 'n'. It does not necessarily mean that the sequence is an AP.
For example, consider the sequence: 1, 4, 9, 16, 25, ...
Here, an - an-1 = (n^2) - (n-1)^2 = 2n - 1, which is not a constant value. But still, the sequence is not an AP because the difference between the terms is not constant.
Reason (R): Common difference d = an - an-1 is constant or independent of n.
This reason is true. In an AP, the common difference 'd' is constant and independent of 'n'. It means that the difference between any two consecutive terms remains the same throughout the sequence.
For example, consider the sequence: 2, 5, 8, 11, 14, ...
Here, an - an-1 = 3, which is a constant value. The sequence follows the AP pattern with a common difference of 3.
Therefore, the reason is true, but the assertion is false. The given sequence cannot be considered an AP solely based on the fact that an - an-1 is not independent of 'n'. The key factor in determining an AP is the constancy of the difference between consecutive terms.
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