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find the G.P. whose 5^(th) term is 48 an...

find the G.P. whose `5^(th)` term is 48 and `8^(th)` term is 384.

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To find the geometric progression (G.P.) whose 5th term is 48 and 8th term is 384, we can follow these steps: ### Step 1: Understand the terms of a G.P. In a geometric progression, the nth term can be expressed as: \[ T_n = A \cdot R^{n-1} \] where \( A \) is the first term, \( R \) is the common ratio, and \( n \) is the term number. ### Step 2: Write equations for the given terms From the problem, we know: - The 5th term \( T_5 = A \cdot R^{4} = 48 \) (1) - The 8th term \( T_8 = A \cdot R^{7} = 384 \) (2) ### Step 3: Set up the equations From equation (1): \[ A \cdot R^{4} = 48 \] From equation (2): \[ A \cdot R^{7} = 384 \] ### Step 4: Divide the second equation by the first To eliminate \( A \), we can divide equation (2) by equation (1): \[ \frac{A \cdot R^{7}}{A \cdot R^{4}} = \frac{384}{48} \] This simplifies to: \[ R^{3} = 8 \] ### Step 5: Solve for \( R \) Taking the cube root of both sides: \[ R = 2 \] ### Step 6: Substitute \( R \) back to find \( A \) Now, substitute \( R = 2 \) back into equation (1): \[ A \cdot (2^{4}) = 48 \] This simplifies to: \[ A \cdot 16 = 48 \] Now, divide both sides by 16: \[ A = \frac{48}{16} = 3 \] ### Step 7: Write the G.P. Now that we have \( A = 3 \) and \( R = 2 \), we can write the G.P.: The terms of the G.P. are: - First term: \( A = 3 \) - Second term: \( A \cdot R = 3 \cdot 2 = 6 \) - Third term: \( A \cdot R^2 = 3 \cdot 2^2 = 12 \) - Fourth term: \( A \cdot R^3 = 3 \cdot 2^3 = 24 \) - Fifth term: \( A \cdot R^4 = 3 \cdot 2^4 = 48 \) - Sixth term: \( A \cdot R^5 = 3 \cdot 2^5 = 96 \) - Seventh term: \( A \cdot R^6 = 3 \cdot 2^6 = 192 \) - Eighth term: \( A \cdot R^7 = 3 \cdot 2^7 = 384 \) Thus, the G.P. is: \[ 3, 6, 12, 24, 48, 96, 192, 384, \ldots \] ### Final Answer: The G.P. is \( 3, 6, 12, 24, 48, 96, 192, 384, \ldots \) ---
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ICSE-GEOMETRIC PROGRESSION -Exercise 11(D)
  1. find the G.P. whose 5^(th) term is 48 and 8^(th) term is 384.

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  2. Find the sum of G.P. : 1+3+9+27+ . . . . .. . to 12 terms.

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  3. Find the sum of G.P. : 0*3+0*03+0*003+0*0003+ . . . . . . . to 8 ter...

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  4. Find the sum of G.P. : 1-(1)/(2)+(1)/(4)-(1)/(8)+ . . . .. . . .. . ...

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  5. Find the sum of G.P. : 1-(1)/(3)+(1)/(3^(2))-(1)/(3^(3))+ . . . .. ....

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  6. Find the sum of G.P. : (x+y)/(x-y)+1+(x-y)/(x+y)+ . . . . .. . . . ...

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  7. Find the sum of G.P. : sqrt(3)+(1)/(sqrt(3))+(1)/(3sqrt(3))+ . . . ....

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  8. How many terms of the geometric progression 1+4+16+64+ . . . . .. . . ...

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  9. If the first term of a G.P is 27 and 8th term is 1/81, then the sum of...

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  10. A boy spends Rs. 10 on first day, Rs. 20 on second day, Rs. 40 on thir...

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  11. The 4^(th) and the 7^(th) terms of a G.P. are (1)/(27) and (1)/(729) r...

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  12. A geometric progression has common ratio = 3 and last term = 486. If t...

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  13. Find the sum of G.P. : 3,6,12, . . . . . . . . ., 1536.

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  14. How many terms of the series 2+6+18+ . . . . . . . . . . . Must be tak...

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  15. In a G.P., the ratio between the sum of first three terms and that of ...

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  16. How many terms of the G.P. (2)/(9),-(1)/(3),(1)/(2), . . . . . . . ....

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  17. If the sum of 1+2+2^(2)+ . . . . . . . . . .+2^(n-1) is 255, find the ...

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  18. Find the geometric mean between : (4)/(9) and (9)/(4)

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  19. Find the geometric mean between : 14 and (7)/(32)

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  20. Find the geometric mean between : 2a and 8a^(3)

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  21. The sum of three numbers in G.P. is (39)/(10) and their product is 1. ...

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