23. Find the number of terms of the AP: -12,-9, -6,..., 21. If 1 is added to each
term of this AP, then find the sum of the terms of the A.P thus obtained.
Answers
Answered by
1
a = -12
d = -9 - (-12) = -9 + 12 = 3
an = 21
21 = -12 + ( n - 1)(3)
21+12 = 3n - 3
33 +3 = 3n
36/3 = n
12 = n
now according to question if 1 is added to each term is this A.P.
-11 , - 8 ,........,22
sum of above A.P. Will be
S = 12/2( -11 + 22 )
S = 6 × 11
S = 66
Answered by
0
Answer:
Pls mark as brainliest!!
Step-by-step explanation:
Attachments:
Similar questions