2]The 8th of an AP is 12 and 12 th term is 8 find the
general term
2
Answers
Answer:
20 - n
Step-by-step explanation:
Let the first term be a and common difference be d. nth term of AP = a + (n - 1)d
In the question:
8th term = 12
a + 7d = 12 ...(1)
12th term = 8
a + 11d = 8 ...(2)
Subtracting (1) from (2), we get
=> (a + 11d) - (a + 7d) = 8 - 12
=> 4d = - 4
=> d = - 1, thus, in (1)
=> a + 7(-1) = 12
=> a = 19
Therefore, let any general term be nth term
=> a + (n - 1)d
=> 19 + (n - 1)(-1)
=> 20 - n
General term of this AP is 20 - n
Answer:
Let the first term be a and common difference be d. nth term of AP = a + (n - 1)d
In the question:
8th term = 12
a + 7d = 12 ...(1)
12th term = 8
a + 11d = 8 ...(2)
Subtracting (1) from (2), we get
=> (a + 11d) - (a + 7d) = 8 - 12
=> 4d = - 4
=> d = - 1, thus, in (1)
=> a + 7(-1) = 12
=> a = 19
Therefore, let any general term be nth term
=> a + (n - 1)d
=> 19 + (n - 1)(-1)
=> 20 - n
General term of this AP is 20 - n