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S(1),S(2), S(3),...,S(n) are sums of n i...

`S_(1),S_(2), S_(3),...,S_(n)` are sums of n infinite geometric progressions. The first terms of these progressions are `1, 2^(2)-1, 2^(3)-1, ..., 2^(n) – 1` and the common ratios are `(1)/(2),(1)/(2^(2)),(1)/(2^(3)), ...., (1)/(2^(n))`. Calculate the value of `S_(1), +S_(2),+ ... + S_(n).`

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To solve the problem, we need to find the sum \( S_1 + S_2 + S_3 + \ldots + S_n \) where each \( S_k \) is the sum of an infinite geometric progression. ### Step 1: Identify the first term and common ratio for each \( S_k \) The first terms of the progressions are given as: - \( a_1 = 1 \) - \( a_2 = 2^2 - 1 = 3 \) - \( a_3 = 2^3 - 1 = 7 \) - ... - \( a_n = 2^n - 1 \) The common ratios are: - \( r_1 = \frac{1}{2} \) - \( r_2 = \frac{1}{2^2} = \frac{1}{4} \) - \( r_3 = \frac{1}{2^3} = \frac{1}{8} \) - ... - \( r_n = \frac{1}{2^n} \) ### Step 2: Use the formula for the sum of an infinite geometric series The sum \( S_k \) of an infinite geometric series can be calculated using the formula: \[ S_k = \frac{a_k}{1 - r_k} \] where \( a_k \) is the first term and \( r_k \) is the common ratio. ### Step 3: Calculate \( S_k \) for each \( k \) 1. **For \( S_1 \)**: \[ S_1 = \frac{1}{1 - \frac{1}{2}} = \frac{1}{\frac{1}{2}} = 2 \] 2. **For \( S_2 \)**: \[ S_2 = \frac{2^2 - 1}{1 - \frac{1}{4}} = \frac{3}{\frac{3}{4}} = 4 \] 3. **For \( S_3 \)**: \[ S_3 = \frac{2^3 - 1}{1 - \frac{1}{8}} = \frac{7}{\frac{7}{8}} = 8 \] 4. **For \( S_4 \)**: \[ S_4 = \frac{2^4 - 1}{1 - \frac{1}{16}} = \frac{15}{\frac{15}{16}} = 16 \] Continuing this pattern, we can see that: \[ S_k = 2^k \quad \text{for } k = 1, 2, 3, \ldots, n \] ### Step 4: Sum \( S_1 + S_2 + S_3 + \ldots + S_n \) Now we need to calculate: \[ S_1 + S_2 + S_3 + \ldots + S_n = 2 + 4 + 8 + \ldots + 2^n \] This is a geometric series where the first term \( a = 2 \) and the common ratio \( r = 2 \). The sum of the first \( n \) terms of a geometric series can be calculated using the formula: \[ S_n = a \frac{r^n - 1}{r - 1} \] Substituting the values: \[ S_n = 2 \frac{2^n - 1}{2 - 1} = 2(2^n - 1) = 2^{n+1} - 2 \] ### Final Answer Thus, the value of \( S_1 + S_2 + S_3 + \ldots + S_n \) is: \[ \boxed{2^{n+1} - 2} \]
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ICSE-SEQUENCE AND SERIES -EXERCISE 14 (f)
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  2. The second term of a G.P. is 2 and the sum of infinite terms is 8. Fin...

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  3. Find the value of 0.23434343434..... regarding it as a geometric serie...

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  4. Evaluate : (a) 0.9bar7 (b) 0.2345

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  5. Find a rational number which when expressed as a decimal will have 1.2...

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  6. If a+b+.... + l is a G.P., prove that its sum is (bl-a^(2))/(b-a) .

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  7. The nth term of a geometrical progression is (2^(2n-1))/(3) for all va...

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  8. A geometrical progression of positive terms and an arithmetical progre...

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  9. In a geometric progression, the third term exceeds the second by 6 and...

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  10. In an infinite geometric progression, the sum of first two terms is 6 ...

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  11. Three numbers are in A.P. and their sum is 15. If 1,4 and 19 be added ...

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  12. Calculate the least number of terms of the geometric progression 5 + 1...

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  13. If S is the sum, P the product and R the sum of the reciprocals of n t...

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  14. Find the sum of the first n terms of the series: 0.2 + 0.22 + 0.222+...

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  15. If (2)/(3)=(x-(1)/(y))+(x^(2)-(1)/(y^(2)))+ ... "To" oo and xy =2 th...

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  16. S(1),S(2), S(3),...,S(n) are sums of n infinite geometric progressions...

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  17. Find three numbers a, b, c between 2 and 18 such that: (i) their sum...

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  18. Three numbers, whose sum is 21, are in A.P. If 2, 2, 14 are added to t...

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  19. If X=1+a+a^(2)+a^(3)+"..."+infty " and " y=1+b+b^(2)+b^(3)+"..."+infty...

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  20. If S(1),S(2), S(3),......, S(p) are the sums of infinite geometric ser...

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