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If a, b, c are in geometric progression,...

If a, b, c are in geometric progression, then prove that :
`(1)/(a^(2)-b^(2))+(1)/(b^(2))=(1)/(b^(2)-c^(2))`

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To prove that \[ \frac{1}{a^2 - b^2} + \frac{1}{b^2} = \frac{1}{b^2 - c^2} \] given that \(a\), \(b\), and \(c\) are in geometric progression, we can start by using the property of geometric progression. ### Step 1: Use the property of geometric progression Since \(a\), \(b\), and \(c\) are in geometric progression, we have: \[ b^2 = ac \] ### Step 2: Rewrite the left-hand side (LHS) We start with the left-hand side: \[ \text{LHS} = \frac{1}{a^2 - b^2} + \frac{1}{b^2} \] ### Step 3: Substitute \(b^2\) in terms of \(a\) and \(c\) Using the relation \(b^2 = ac\), we can rewrite \(a^2 - b^2\): \[ a^2 - b^2 = a^2 - ac = a(a - c) \] Now substituting this back into the LHS: \[ \text{LHS} = \frac{1}{a(a - c)} + \frac{1}{ac} \] ### Step 4: Find a common denominator The common denominator for the two fractions is \(ac(a - c)\): \[ \text{LHS} = \frac{c}{ac(a - c)} + \frac{(a - c)}{ac(a - c)} \] ### Step 5: Combine the fractions Now we can combine the fractions: \[ \text{LHS} = \frac{c + (a - c)}{ac(a - c)} = \frac{a}{ac(a - c)} \] ### Step 6: Simplify the expression Now simplify the expression: \[ \text{LHS} = \frac{1}{c(a - c)} \] ### Step 7: Rewrite the right-hand side (RHS) Now we will rewrite the right-hand side: \[ \text{RHS} = \frac{1}{b^2 - c^2} \] Using \(b^2 = ac\): \[ b^2 - c^2 = ac - c^2 = c(a - c) \] Thus, the RHS becomes: \[ \text{RHS} = \frac{1}{c(a - c)} \] ### Step 8: Compare LHS and RHS Now we see that: \[ \text{LHS} = \frac{1}{c(a - c)} = \text{RHS} \] Thus, we have proved that: \[ \frac{1}{a^2 - b^2} + \frac{1}{b^2} = \frac{1}{b^2 - c^2} \] ### Conclusion Hence, the statement is proven. ---

To prove that \[ \frac{1}{a^2 - b^2} + \frac{1}{b^2} = \frac{1}{b^2 - c^2} \] given that \(a\), \(b\), and \(c\) are in geometric progression, we can start by using the property of geometric progression. ...
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NAGEEN PRAKASHAN ENGLISH-SEQUENCE AND SERIES-Miscellaneous Exercise
  1. If a, b, c are in geometric progression, then prove that : (1)/(a^(2...

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  2. 32. Show that the sum of (m+n)^(th) and (m-n)^(th) terms of an A.P. is...

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  3. The sum of three numbers in A.P. is 27, and their product is 504, find...

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  4. Let the sum of n, 2n, 3n terms of an A.P. be S1,S2and S3, respectively...

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  5. Find the sum of all numbers between 200 and 400 which are divisible...

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  6. Find the sum of integers from 1 to 100 that are divisible by 2 or 5...

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  7. Find the sum of all two digit numbers which when divided by 4, yiel...

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  8. If f is a function satisfying f(x+y)=f(x)f(y)for all x ,y in Xsuch t...

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  9. The sum of some terms of G. P. is 315 whose first term and the comm...

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  10. The first term of a G.P. is 1. The sum of the third and fifth terms is...

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  11. The sum of three numbers m GP is 56. If we subtract 1.7,21 from the...

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  12. A G.P. consists of an even number of terms. If the sum of all the t...

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  13. The sum of the first four terms of an A.P. is 56. The sum of the la...

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  14. If (a+b x)/(a-b x)=(b+c x)/(b-c x)=(c+dx)/(c-dx)(x!=0),then show that...

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  15. LetS be the sum, P the product, and R the sum of reciprocals of n term...

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  16. The p^(t h),q^(t h)and r^(t h)terms of an A.P. are a, b, c, respectiv...

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  17. If a (1/b+1/c),b(1/c+1/a),c(1/a+1/b)are in A.P., prove that a, b, c a...

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  18. If a, b, c, d are in G.P., prove that (a^n+b^n),(b^n+c^n),(c^n+a^n)ar...

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  19. If a and b are the roots of x^2-3x+p=0and c, d are roots of x^2-12 x+...

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  20. The ratio of the A.M. and G.M. of two positive numbers a and b, is m ...

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  21. If a ,\ b ,\ c are in A.P. b ,\ c ,\ d are in G.P. and 1/c ,1/d ,1/e a...

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