CBSE Class 10 Answered
if a times the ninth term of an ap equals 12 times the twelth term show that 21st term is zero
Asked by ABHILASHA | 16 Jan, 2019, 10:57: AM
Expert Answer
It is given in the posted question : " a times of 9th term of an A.P equals 12 times of 12th term " .
I back calculated from the given answer and found that it should be " 9 times of 9th term of an A.P equals 12 times of 12th term " .
Hence I guess it is 9 times of 9th term
let a be the first term and d be the common difference os A.P
9(a+8d) = 12(a+11d)
Hence 3a+60d = 0 or a+20d = 0
since a+20d is 21st term of an A.P, it is proved that 21st term is zero
Answered by Thiyagarajan K | 16 Jan, 2019, 01:22: PM
Application Videos
Concept Videos
CBSE 10 - Maths
Asked by yalagondanikhil | 16 Apr, 2024, 12:25: PM
ANSWERED BY EXPERT
CBSE 10 - Maths
Asked by rrajansinghakb199 | 08 Apr, 2024, 05:12: PM
ANSWERED BY EXPERT
CBSE 10 - Maths
Asked by nagalaxmidurgarao937 | 08 Apr, 2024, 01:42: PM
ANSWERED BY EXPERT
CBSE 10 - Maths
Asked by mraniruddha03 | 02 Apr, 2024, 06:44: PM
ANSWERED BY EXPERT
CBSE 10 - Maths
Asked by muttenenimalleswarrao | 29 Mar, 2024, 08:32: PM
ANSWERED BY EXPERT
CBSE 10 - Maths
Asked by pathakvaishnavi9139 | 23 Mar, 2024, 10:45: AM
ANSWERED BY EXPERT
CBSE 10 - Maths
Asked by mustafahssn786 | 23 Mar, 2024, 06:25: AM
ANSWERED BY EXPERT
CBSE 10 - Maths
Asked by choudharyniki001 | 22 Mar, 2024, 08:49: AM
ANSWERED BY EXPERT
CBSE 10 - Maths
Asked by jagdishdabang79 | 18 Mar, 2024, 08:40: PM
ANSWERED BY EXPERT