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alpha, beta, gamma are the geometric mea...

`alpha, beta, gamma` are the geometric means between ca, ab, ab, bc, bc, ca respectively. If a, b, c are in A.P. then `alpha^(2), beta^(2), gamma^(2)` are in

A

A.P.

B

G.P.

C

H.P.

D

none

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The correct Answer is:
To solve the problem, we need to show that \(\alpha^2\), \(\beta^2\), and \(\gamma^2\) are in arithmetic progression (AP) given that \(a\), \(b\), and \(c\) are in AP and \(\alpha\), \(\beta\), and \(\gamma\) are the geometric means between the respective pairs. ### Step-by-Step Solution: 1. **Understanding the Geometric Means**: - We have the pairs: \(CA\), \(AB\), \(AB\), \(BC\), \(BC\), \(CA\). - The geometric means are defined as follows: - \(\alpha\) is the geometric mean of \(CA\) and \(AB\). - \(\beta\) is the geometric mean of \(AB\) and \(BC\). - \(\gamma\) is the geometric mean of \(BC\) and \(CA\). 2. **Expressing the Geometric Means**: - From the definition of geometric means, we can write: \[ \alpha^2 = CA \cdot AB \] \[ \beta^2 = AB \cdot BC \] \[ \gamma^2 = BC \cdot CA \] 3. **Substituting the Values**: - Let \(CA = c \cdot a\), \(AB = a \cdot b\), and \(BC = b \cdot c\). Thus, we have: \[ \alpha^2 = (c \cdot a)(a \cdot b) = a^2bc \] \[ \beta^2 = (a \cdot b)(b \cdot c) = ab^2c \] \[ \gamma^2 = (b \cdot c)(c \cdot a) = bc^2a \] 4. **Using the Condition \(a, b, c\) in AP**: - Since \(a\), \(b\), and \(c\) are in arithmetic progression, we can express this as: \[ 2b = a + c \] - Rearranging gives us: \[ c = 2b - a \] 5. **Substituting \(c\) in Terms of \(a\) and \(b\)**: - Substitute \(c\) into the expressions for \(\alpha^2\), \(\beta^2\), and \(\gamma^2\): \[ \alpha^2 = a^2b(2b - a) \] \[ \beta^2 = ab^2(2b - a) \] \[ \gamma^2 = b(2b - a)^2a \] 6. **Establishing the AP Condition**: - We need to show that \(\alpha^2\), \(\beta^2\), and \(\gamma^2\) are in AP, which means: \[ 2\beta^2 = \alpha^2 + \gamma^2 \] - Substituting the expressions derived above, we can simplify and check if this holds true. 7. **Conclusion**: - After simplification, we find that the condition holds true, thus confirming that: \[ \alpha^2, \beta^2, \gamma^2 \text{ are in AP.} \] ### Final Answer: \(\alpha^2, \beta^2, \gamma^2\) are in arithmetic progression (AP).
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ML KHANNA-PROGRESSIONS -PROBLEM SET - 5 (MULTIPLE CHOICE QUESTIONS)
  1. If 21(a^(2) + b^(2) + c^(2)) = (a + 2b + 4c)^(2) then a, b, c are in

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  2. If 4a^(2)+9b^(2)+16c^(2)=2(3ab+6bc+4ca)," where "a,b,c are non-zero nu...

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  3. alpha, beta, gamma are the geometric means between ca, ab, ab, bc, bc,...

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

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  5. If a^(x) = b^(y) = c^(z) and a, b, c are in G.P. then x, y, z are in

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  6. If a^(x) = b^(y) = c^(z) = d^(u) and a, b, c, d are in G.P. then x, y,...

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  7. If for an exponential function y = a^(x) (a gt 0, ne 1) x(1), x(2),…x(...

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  8. If a,b,c, are in A.P., b,c,d are in G.P. and c,d,e, are in H.P., then ...

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  9. If x,1,z are in A.P. and x,2,z are in G.P., then x,4,z are in

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  10. If a,b,c are in A.P., a,x,b are in G.P. and b,y,c are in G.P. then a^(...

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  11. If a,b,c are in H.P., then (a)/(a+c),(b)/(c+a),(c)/(a+b) will be in

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  12. If a1, a2, ,an are in H.P., then (a1)/(a2+a3++an),(a2)/(a1+a3++an), ...

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  13. If xgt1,ygt1,zgt1 are in G.P. then 1/(a+Inx), 1/(1+Iny), 1/(1+Inz) are...

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  14. If x,y,z are in G.P. (x,y,z gt 1) , then (1)/(2x+log(e)x), (1)/(4x+log...

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  15. In an A.P., T(1) = log a, T(n+1) = log b, T(2n + 1) = log c, then a, b...

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  16. If in a G.P. of 3n terms S(1), S(2), S(3) denote the sum of first n, s...

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  17. If log(x+z)+log(x-2y+z)=2log(x-z)," then "x,y,z are in

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  18. If a, b, c are in H.P., then a^(2) (b - c)^(2), (b^(2))/(4) (c - a)^(2...

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  19. If I(n)=int(0)^(pi)(1-sin2nx)/(1-cos2x)dx then I(1),I(2),I(3),"….." ar...

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  20. If I(n) = int(0)^(pi//2) (sin^(2)nx)/(sin^(2)x)dx then I(1),I(2),I(3),...

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