InterviewSolution
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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)` |
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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 | |
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