Saved Bookmarks
| 1. |
The 8th term of an A.P. is 32 and its 12th term is 52. Find the A.P. |
|
Answer» let rstterm of this A.P. be a , commom difference be dNow, nth term of A.P. is given by:a+(n-1)dso, its 8th term = a+(8-1)d = a+7dbut 8th term of A.P. is 32so, a+7d = 32 ...(1)similarly, 12th term = a+(12-1)d = a+11d = 52so, a+11d= 52 ....(2)Subtracting eq (1) from (2),a+11d - (a+7d) = 52 - 32=》4d = 20=》d= 5putting the value of d in (1),a+7d = a+7×5 = 32=》a+35 = 32=》 a = -3Now, a = -3 and d = 5so, second term of A.P. = a+ d = -3+5 = 2similarly 3rd term = a+2d = -3 + 5×2 = 7so, Required A.P. is : -3,2,7,12,17 ........ |
|