1.

किसी गुणोत्तर श्रेणी के n पदों का योग `S_(1),2n`पदों का योग `S_(2)`तथा 3n पदों का योग `S_(3)` हों,तो सिध्द कीजिए कि `S_(1)(S_(3)-S_(2))=(S_(2)-S_(1))^(2)`

Answer» प्रश्नानुसार `" " S_(1)=(a(r^(n)-1))/(r-1),S_(2)=(a(r^(2n)-1))/(r-1),S_(3)=(a(r^(3n)-1))/(r-1)`
`rArr " "S_(3)-S_(2)=(a)/(r-1)(r^(3n)-r^(2n))=(a(r^(n)-1))/(r-1).r^(2n)`
`:. " "S_(1)(S_(3)-S_(2))=(a(r^(n)-1))/(r-1).(a(r^(n)-1))/(r-1)r^(2n)=[(a(r^(n)-1))/(r-1)r^(n)]^(2)" "`......(i)
तथा `" "S_(2)-S_(1)=(a)/(r-1)(r^(2n)-r^(n))=(a(r^(n)-1))/(r-1).r^(n)" "`...(ii)
समीकरण (i)व (ii)से,
`S_(1)(S_(3)-S_(2))=(S_(2)-S_(1))^(2)" "` यही सिध्द करना था |


Discussion

No Comment Found

Related InterviewSolutions