Black Advanced Problems in Mathematics
- Exam
- Black Advanced Problems in Mathematics
- Subject
- Mathematics
- Chapter
- Sequences and Series
Black Advanced Problems in Mathematics · Mathematics · Sequences and Series
If S_1, S_2 and S_3 are the sums of first n natural numbers, their...
If and are the sums of first natural numbers, their squares and their cubes respectively, then
Options
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Correct answer
4
Step-by-step solution
We know the standard formulas:
\left(\frac{n(n+1)}{2}\right)^2S_3 = S_1^2S_3 = S_1^2\frac{S_1^4 S_2^2 - S_2^2 (S_1^2)^2}{S_1^2 + S_3^2} = \frac{S_1^4 S_2^2 - S_2^2 S_1^4}{S_1^2 + S_3^2} = \frac{0}{S_1^2 + S_3^2} = 0.